The day before:

Preparing the dough (la "détrempe"):

In the bowl of your stand mixer, add in 2 1/2 cups of all-purpose flour and 1 1/2 tsp of salt. With a paddle attachment, mix on low-medium speed to mix the dry ingredients together. Then add in 2/3 cups of cool water and 5 tbsp of unsalted butter that's been melted. Continue to mix on low-medium speed just until the mixture is combined. Stop the mixer. Scrape down the paddle attachment and the sides of the bowl. Avoid over-mixing.

Switch to a dough hook attachment, and knead the dough just till it starts to look smooth. Avoid overworking the dough, as you want to minimize gluten formation and make the dough tough.

Roll it into a square that's 10" by 10". Sprinkle with flour as needed to prevent dough from sticking to the counter. Transfer it onto a sheet pan lined with parchment paper, cover tightly with plastic wrap and leave it in the fridge for 30 minutes for the gluten to relax a bit and for the dough to get cold before laminating. This is called "la détrempe".

Preparing the butter block ("le beurrage"):

While the dough is in the fridge, take 18 tbsp of cold unsalted dry butter or European-style butter and cut them in half lengthwise so you end up with thin long pieces of butter.

Take a large piece of parchment paper, and lay it on a clean flat surface. Measure out 6" by 6" on the piece of parchment paper, and fold the sides of the parchment paper so that you have sort of an 6" by 6" shaped envelope. Your piece of parchment paper should be big enough that the folded-up sides cover the 6" by 6" square completely.

Place the butter pieces inside the 6" x 6" square and enclose the envelope and flip the envelope over. When the butter has softened a bit, gently roll the butter with a rolling pin till the pieces of butter start to blend into each other. Continue rolling and massaging the butter with a rolling pin till it reaches the edges of the folded parchment paper envelope, so that the butter makes a square that is 6" by 6". Place this in the fridge for 30 minutes.

Laminating the dough:

After 30 minutes in the fridge, take the détrempe dough and the beurrage block out of the fridge. To laminate the dough, the dough and the butter should be cool but also soft and pliable during the lamination process. If either is too firm, let them sit at room temperature a bit to warm up.

NOTE: If you have a digital thermometer, the butter should ideally be between 55 to 60 degrees Fahrenheit (13 to 16 degrees Celsius) when folding and rolling.

Place the beurrage block in the middle of the détrempe at a 45-degree angle by inverting it onto the dough while still on the parchment paper so that it looks like a diamond of butter inside the square of dough.The butter will be somewhat stuck to the parchment paper, so you can use the parchment paper to get the right placement. Then peel off the parchment paper.

Fold the four flaps of dough into the center over the butter, stretching the dough a bit, and pinch the dough together to seal the butter inside.

Lightly flour the counter surface, and with a rolling pin, roll the dough into a rectangle that's 8" by 12". Use the rolling pin to roll and even it out. Do your best to make a perfect 8" by 12" rectangle with straight edges and 90-degree corners. Before folding, use a pastry brush to brush off any excess flour on the top surface (excess flour will prevent the layers from sticking together).

Fold one third of the dough into the center. Pat it down so that the two layers stick together. Brush off any excess flour from the top surface of this fold, then fold the opposite end over and onto this first fold. This is called a "letter fold", as it's like folding a letter. Try to make everything neat and make the edges line up as much as possible. Wrap the dough tightly with plastic wrap and let it rest in the fridge for 30-40 minutes, to let it return to the 55 to 60 F (13 to 16 C) range.

When it's within that ideal temperature range, remove the plastic wrap. Rolling the longer edge to 12" long, roll it out into an 8" by 12" rectangle again using the same technique as before. Use a pastry brush to brush off any excess flour on the top surface and repeat the letter fold, i.e. fold one third of the dough into the center. Pat it down so the two layers stick together. Brush off any excess flour from the top surface of this fold, and then fold the opposite end over and onto this first fold.

Gently pat and press the dough a bit to compress the layers together and make sure all the edges are neat and aligned. You have now done 2 turns of dough. Wrap the dough tightly with plastic wrap and let it rest in the fridge for 30-40 minutes to let it return to the 55 to 60 F (13 to 16 C) range.

When it's within that ideal temperature range, remove the plastic wrap and repeat the above steps 4 and 5 (the letter fold) four more times, completing 6 turns in total, refrigerating for 30 minutes after each turn to let the butter and dough return to the 55 to 60 F (13 to 16 C) range. After 6 turns, wrap it tightly in plastic wrap, and leave it in the fridge overnight.

Next day:

Take the dough out of the fridge and let it come 55 to 60 F (13 to 16 C) range. Roll it into a rectangle that's 6" x 12". Cut this rectangle in half to create two squares that are 6" x 6". Wrap each square in plastic wrap, and refrigerate for a minimum of 1 hour.

The almond cream:

In the bowl of your stand mixer, add in 5 tbsp of unsalted butter. With a paddle attachment, mix on low-medium speed till the butter is a smooth and creamy consistency. Stop the mixer

Add in 1/2 cup of granulated sugar and mix on medium speed for 1 to 2 minutes till the sugar and butter are creamed together and smooth, scraping down the bowl and paddle attachment as needed.

Then add in 1 large egg, 1 tsp of almond extract, 2 tsp of rum, and 1/2 tsp of lemon zest. Continue mixing just until all the wet ingredients are combined and well blended, scraping the bowl and paddle attachment in between as needed.

Turn the mixer down to low-medium speed, add in 2/3 cup of almond flour, 1 tsp of all-purpose flour, and 1/4 tsp of salt. Continue mixing just until the almond flour is well combined and the mixture is smooth, scraping the bowl and paddle attachment as needed.

Transfer this almond cream mixture into a piping bag with no tip, just a 1/2" diameter hole, and refrigerate for a minimum of 1 hour before piping.

Sugar syrup:

In a small saucepan, add in 1/4 cup of granulated sugar and 1/4 cup of water. Bring this to a boil over low-medium heat till all the sugar dissolves. Set this aside to cool.

Assembling the cake:

Beat 1 egg to make an egg wash and set this aside. Line a large sheet pan (we use a 13" by 18" pan) and line it with parchment paper.

Lightly grease your counter and rolling pin. Use oil to prevent the dough from sticking at this point as flour can cover up the dough-butter layers. Use a thermometer to make sure the butter and dough are between 55-60 F (13-16 C) before this final rolling step.

Take 1 square of dough at a time out of the fridge (so the other square stays as cold as possible), roll it out into a roughly 11" x 11" square. Transfer this 11" x 11" dough square onto the prepared parchment paper-lined sheet pan. Lightly press a 9" cake ring into the middle of the square to leave a circular impression. Brush the marked-out 9" circle with the prepared egg wash.

Pipe out the cold almond cream inside the 9" circle, leaving a 1-inch border free of almond cream. I like to start piping with the outside border first to ensure that I keep that 1-inch border, which is very important. Then fill in that initial outer piping of almond cream with consecutive circles, then pipe a second layer of almond cream circles, till all the almond cream is all used up. Use an offset spatula to evenly spread out the almond cream into a flat and even layer as much as possible.

Place a whole almond (or porcelain charm, if you have one), which is called "la fève", into the almond cream. Let this rest in the fridge while working on the second half of the dough.

Lightly grease your counter and rolling pin again. Take the second half of dough, let it come to the 55-60 F (13-16 C) range, and roll it out into a roughly 11" x 11" square. Take the baking sheet out of the fridge, re-apply egg wash on the 1-inch border of dough without almond cream, and lay the second dough square over the first one, pressing down on the edges to encase the almond cream and push out any air.

Use the same 9" cake ring to press and seal the 2 layers of dough together, also effectively cutting out the cake, which should leave a 1-inch border of dough free of any almond cream filling. Remove the excess dough. You can shape this excess dough into mini croissants, freeze them, and bake for later (just brush frozen mini croissants with egg wash and bake frozen croissant dough at 425 F for 15-20 minutes, depending on their size).

Use your fingers to press the two layers of dough together firmly. Using your fore-finger and middle finger, place two fingers on the 1-inch border facing out from the center of the galette, then use the back of a bread knife to scallop the edges by drawing it towards you between your two fingers, about 1/2" deep. This will create a decorative border around your galette, and also ensure the two layers of dough are firmly crimped together.

Brush the top of the cake with the egg wash, stopping at the 1-inch border and preventing the egg wash from dripping down the sides of the cake, as we do not want to lock the layers of butter and prevent the cake from rising. Rest in the fridge for 15 minutes. Then brush the top of the cake with another layer of egg wash, again stopping at the 1-inch border and preventing the egg wash from dripping down the sides of the cake. Rest in the fridge for 15 minutes.

Finally, take the cake out of the fridge and use a sharp knife to score a design at the top of the cake with lines radiating from the center towards the edges. For more even scoring, mark the center of the cake first. Then score the 4 quadrants. Then finish scoring each quadrant of the cake. Be careful not to cut all the way through the dough. We're only making a slight indentation to create a pattern. Poke a large vent hole in the center, and 8 additional slits distributed evenly over the surface, hiding the slits in the scoring that you've created. These vent holes will allow steam to escape and prevent the almond paste from leaking out from the sides during baking. Rest the cake in the fridge for 30 minutes.

Preheat your oven to 410 F (210 C). Bake your galette des rois at 410 F (210 C) for 15 minutes. Then turn the temperature down to 355 F (180 C) and continue baking for another 25 minutes, or until the cake is beautifully golden brown. Don't be afraid to let it become deeply browned, as this caramelization gives the butter and crust an amazing flavor.

Take the cake out of the oven, and immediately brush the top with the prepared sugar syrup very generously. Let it cool on the baking sheet on a wire rack for at least 15 minutes before serving. Serve warm or at room temperature. Enjoy!