Prepare 2 sheets of parchment paper, if not using already marked silicone mats. Draw 1¼ inch circles ~ 1inch apart on the paper. Place each parchment paper marked-side down on separate baking sheets.
Use a scale and weigh out powdered sugar and almond flour. Pulse both in a food processor until well combined. Sift the mixture using a rubber spatula to press against the mixture to help it pass through. Discard any course mixture left over.
In the clean bowl of a stand mixer (or use a hand mixer), whisk the egg whites using the whisk attachment on medium speed (level 4, of a stand mixer) until frothy. Increase the speed to medium high (levels 6-8) and gradually add in the sugar until stiff, glossy peaks form. This will take ~ 5 minutes.
At this point, you can divide the recipe for 2 different flavors. If so, divide the mixture into 2 separate bowls and halve the rest of the ingredients continuing to follow the recipe as directed below.
Sift in the almond-sugar mixture and carefully fold 40 times (yes, you should count) the mixture into the egg whites. Each fold should resemble a figure 8 pattern cutting through the middle with each fold using a rubber spatula. Stop after the 40th fold and add food coloring and extracts. Continue to fold another 25-35 times. A good mix will require ~65-75 folds. Fold until the batter is smooth and falls off the spatula in a thin flat ribbon (like oozing lava). If not, fold a little more.
To test the batter, let the batter ooze off the spatula and wait for about 20 seconds to see if the batter flattens out a bit on its own and oozes back into the batter. You could also drop a small amount on a plate and if the peaks retreat into the batter within 10 seconds, it’s ready. If not, keep folding. Do not overmix.
Transfer the batter to a pastry bag fitted with a ⅜- or ½-inch tip. If you don’t have a pastry bag, place a bottom corner of a zip-topped quart (for half a recipe) or gallon-sized bag (for full recipe) in a drinking glass. Scoop the batter in the bag and cut off the corner tip at the bottom of the glass where the batter should be resting. You can place a small dot of macaron batter in each corner of a baking sheet to secure the parchment paper to the baking sheet. Pipe batter into 1¼- ½ -inch rounds, swirling the tip off to the side to create a flatter top. Repeat, spacing cookies at least 1 inch apart, until sheets are full. IMPORTANT: Tap the sheets against the counter loudly to remove air bubbles. If the air bubbles are large and won't pop, lighly poke them with a sharp knife.
Let the cookies sit at room temperature until the tops are no longer sticky to the touch (~15 minutes- 1 hour depending on humidity). They should look dry and matte.
Place oven rack in the lower third position and preheat to 350°F/177˚C. Place one of the baking sheets with cookies on them in another baking sheet. A double baking sheet will prevent the cookies from getting too hot. If you only have 2 baking sheets just slide the parchment paper with one set of dried cookies out onto a counter.
Drop the oven temperature down to 325˚F/163˚C when you place the cookies in the oven. Bake one pan at a time. Set the timer for 7 minutes baking, then drop the temperature to 300°F/149˚C, and rotate the pan. Bake for another 6-11 minutes for a total of 13-18 minutes. After removing a pan raise temperature back to 350°F/177˚C until it is preheated to that mark. Drop the temperature back down to 325˚F/163˚C when you add the next pan. Repeat above steps dropping the temp to 300°F/149˚C and rotating the pan at 7 minutes.
You should start to see the “foot” (pied) about 5 minutes. The cookies are done when you gently touch the feet and they are dry. If the feet are sticky or they slightly shift away from the tops, then they need more time. Just add another minute and continue to do so until they are a solid unit.
Remove the baking sheet from the oven and set aside to cool for a few minutes. Transfer the entire sheet of parchment paper with cookies on a wire rack to cool completely. Gently peel the cookies from the parchment paper. If the macarons seem a little wet place them back in the oven with the door open to dry out for a few minutes. The macarons are not done if they are sticking to the parchment paper. Slide a sharp knife between the cookies and the paper if they are a little tacky as you remove them.
Spoon or pipe filling onto the flat side of one cookie and top with another. Gently twist the top on the filling so that it spreads to the edges. You can taste them immediately BUT they should be transferred to an airtight container or wrapped with plastic and refrigerated at least 24 hours to allow them to soften before eating. Store up to 5 days in the fridge or freeze 4-5 months for longer storage. Thaw for 30 minutes on the counter prior to eating them from the freezer.