Ube Meringue Cookies:

Take 3 eggs and separate the yolks and whites into 2 separate bowls. Cover the egg yolks with plastic wrap but do not cover the egg whites. Let them rest at room temperature for about 2 to 3 hours, allowing them to come to room temperature. This will also dehydrate the egg whites a bit, which is helpful for making macaron batter.

Prep a large bowl with a sieve on top. Measure out 1 1/2 cups of almond flour and 1 cup of powdered sugar. Note: both the almond flour and powdered sugar should not be packed when measuring.

Lay out a piece of parchment paper on the counter and put your measuring cup on it. Loosely transfer out your almond flour into the measuring cup without packing it in at all. Then level it with a straight edge. Place this almond flour into the sieve. If you're using a weighing scale, you should get approximately 140 g of almond flour.

Measure 1 cup of powdered sugar in the same way, and add it to the sieve. If you're using a weighing scale, you should get approximately 120 g of powdered sugar.

Once the almond flour and powdered sugar are in the sieve on top of a large mixing bowl sift them in. Pinch large clumps to break them up to pass through the sieve. Press them in as needed.

Using another large bowl, sift the almond flour / powdered sugar mixture through the sieve once more. Break up any large clumps with your fingers helping to press it through the sieve. Do this once more back into the first bowl, so that the almond flour / powdered sugar mixture has been sifted a total of 3 times. This ensures that there are no clumps in the dry ingredients.

In the bowl of your stand mixer, add in the 3 room temperature dehydrated egg whites, 1/4 tsp salt, 1/4 tsp cream of tartar, and 3 tbsp of granulated sugar. Whisk together till they are combined.

Set up a double-boiler and heat the egg white mixture on low heat while continuing to whisk, till the sugar is dissolved (when it feels sticky to touch, and you hardly feel the grains of sugar anymore). If you have a thermometer, it should reach 160 F (70 C).

Take it off the water bath and attach to the stand mixer. With the whisk attachment, beat on medium-high speed and slowly add in the remaining 3 tbsp of granulated sugar. When all the sugar has been added, you can add 1/8 tsp of ube extract to give the cookies a subtle ube flavor and light purple tint.

Continue beating until the meringue until you see stiff glossy peaks. Stop the mixer and detach the mixing bowl from the stand-mixer. Fold in the fine almond flour-powdered sugar mixture one-third at a time.

When the dry ingredients are fully incorporated into the meringue, continue folding, making sure you scrape the bottom and sides thoroughly with every stroke of the spatula while folding. At this point the batter should be more "stiff", and we are now slowly knocking out air from the meringue, making it more "runny", to obtain the ideal consistency for macarons. Frequently test the batter's consistency by doing a "ribbon test". The goal is to create a consistency where the batter looks thick but flows from the spatula to create a ribbon shape without breaking the batter. If the batter breaks when making the ribbon shape, it means the batter is still too "stiff": continue folding and try again. As soon as your batter reaches this consistency (you can make ribbon shape without breaking the batter), stop folding.

Note: Err on the side of caution. It is better to have a batter that is on the stiffer side than a batter that is too runny. Some air will get knocked out when transferring to the piping bag and during piping. If you've over-folded and the batter is too runny, the macarons won't rise and will end up flat.

Prepare a 13" x 18" sheet pan by fitting them with parchment paper. Use a little of the meringue mixture on the 4 corners of the pieces of parchment paper to hold them in place.

Take a pastry bag fitted with a medium round tip. I'm using a #2A tip. Spoon the batter into the piping bag.

Keeping the piping bag perpendicular to the sheet pan at all times, pipe out small round blobs of meringue onto the parchment paper by squeezing the bag, about a tablespoon
worth of batter. When you've squeezed the amount you want, stop squeezing, then lift the tip with a circular motion (maintaining the perpendicular positioning). Pipe out all of the batter onto the parchment paper-lined sheet pan. This batter should make about 30 cookies per sheet pan, 6 cookies per row in 5 rows, making 15 macarons, depending on how big you pipe the circles.

Careful that the parchment paper doesn't slip off the sheet pan, gently tap the sheet pan onto the counter several times to help release any air bubbles from the batter. Be careful not to tap too forcefully, or the circles of batter will flatten and spread too much. Use a toothpick to pop any air bubbles at the surface that haven't popped.

Let the formed discs of batter rest at room temperature for about 30 minutes to 1 hour. The discs should lose their shine as a skin forms on the surface. The cookies are ready when the surfaces feel dry to the touch and your fingertips don't pick up batter after touching them.

Place 1 oven rack in the middle position. Preheat your oven to 300 F (150 C). Bake the sheet pans one at a time to avoid uneven baking. Bake the cookies for 8 minutes, then rotate the tray, and continue baking for another 8 minutes. For a total baking time of 16 minutes, or until the tops of the cookies no longer look wobbly. The top surface should look smooth while the outer circumference of the cookies should have a "textured" ring after baking.

Let the cookies cool in the pans completely to room temperature. Detach the cookies from the parchment paper by lifting up a corner of the parchment paper, and with your fingers under the parchment paper, carefully peeling the parchment paper the cookie. Transfer the detached cookie on a flat surface. Do this for all the cookies.

Ube Buttercream:

Take 12 tbsp of unsalted butter (1 1/2 sticks) and slice them into 1-inch cubes. Let them come to room temperature.

Place the 3 egg yolks (leftover yolks from macaron cookies) into the bowl of your stand mixer. With the whisk attachment, whip on high speed for about 8 minutes, until thick and lemon-yellow in color.

In a small heavy bottomed saucepan combine 1/3 cup of granulated sugar and 1/4 cup of water. Set over medium heat, till sugar dissolves. Once sugar has dissolved, use a candy thermometer to monitor the temperature of the sugar. Turn the heat to the highest possible level, and heat mixture to the soft ball stage, till the thermometer reads 235 F (110 C). Immediately remove from the heat. With this small amount of sugar-water, it will be shallow in the pan. So you may have to tilt the sauce pan so that the candy thermometer can get a more accurate reading. Do not let it heat past 235 F (110 C), or it will become too hard to mix with the egg yolk.

With the mixer running on high speed, carefully drizzle the hot sugar syrup into the egg yolk mixture in a slow steady stream. This syrup needs to be hot enough so it's at the soft ball stage, and to also "cook" and pasteurize the egg yolks to make them safe to eat. Once all the sugar syrup has been added, stop the mixer to scrape down the sides of the bowl for any unmixed sugar droplets that may have splattered to the side, then turn the mixer back on to medium-high speed and continue to whipping until the mixture has cooled to room temperature, which may take about 5 to 10 minutes.

When the yolk-sugar mixture has cooled to room temperature, turn down the mixer to medium speed, add the 12 tbsp of softened room temperature butter one cube at a time, allowing each piece of butter to be incorporated before adding the next. Once all the butter has been added, stop the mixer. Add in 1 tsp ube extract and 1/4 tsp of salt. Scrape down the sides as needed. Continue to beat on high speed until buttercream is silky and smooth - another 2 minutes.

NOTE: The butter will melt if the egg-sugar mixture is too hot. If you notice the butter separating, cool down the sides of the mixing bowl by placing it in an ice-bath. Alternatively, you can put the bowl in the fridge for a few minutes to cool the contents down before adding in more butter. Eventually, the buttercream should come together.

Assembling the Macarons:

Attach an open star tip (I use a #21 tip) to a clean piping bag, and fill the piping bag with the ube buttercream (use a small round tip, like a #12, if you don't want the filling to look textured)

Pipe the ube buttercream onto the back of half of the cookies. As you're piping onto one cookie, try to find a second cookie that matches in terms of size and shape and lay it next to the cookie that was piped. This way your finished macarons will be as even-looking as possible.

Once half the cookies have filling piped onto them, use the other half of the cookies (should be set right next to piped cookie) to form the macaron sandwiches.

You can eat these immediately, or let them rest in the fridge overnight to mature. This will allow the moisture from the ube buttercream to set and soak into the inside of the cookie, creating variation in the texture.

The finished macarons will keep in the fridge for up to 1 week. Enjoy!