What You Need
For the macarons
cooking spray
226g powdered sugar
98g superfine almond flour
3 large egg whites, at room temperature
1/4 teaspoon cream of tartar
kosher salt
40g superfine sugar
8 drops any color food coloring
For the buttercream
1 stick unsalted butter, room temperature
3/4 cup powdered sugar
1 teaspoon vanilla paste
What To Do
Preheat your oven to 300 degrees and prepare two baking sheets by spraying them with cooking spray, then line them with parchment paper. Place a fine mesh sieve over a large bowl and sift 1 3/4 cup powdered sugar with the almond flour. Press is thoroughly until there are no more than 2 tablespoons of solid left. Throw out the remaining solids.
In the bowl of a stand mixer or using a hand mixer, beat together the egg whites, cream of tartar, and a pinch of salt until the mixture is frothy. Increase the spreed to medium high and slowly add in the sugar, and then continue to beat on medium high until you have reached stiff peaks that are glossy, which will take about 2 to 3 minutes.
Beat in the food coloring until it is thoroughly combined, which should take about 30 seconds. Gently fold in the dry ingredients using the spatula until it is a thick texture that resembles flowing lava, which takes about 2 minutes.
Transfer the batter into a pastry bag with a 1/4 inch tip. Pipe the batter into circles with a 1 inch diameter, with about 1 inch placed apart. Gently tap the baking sheet on the counter several times to get rid of air bubbles that may have formed. Allow the batter to sit for about 45 minutes before putting in the oven.
Bake the sheets one at a time, making sure to rotate halfway through until they have risen, for about 13 to 14 minutes. Allow them to cool for 10 to 15 minutes before slowly and gently peeling the parchment paper away and placing on a cooling rack.
For the buttercream, beat together the butter and 3/4 cup powdered sugar and vanilla paste until everything is smooth and fluffy. Spread it on or pipe it onto the one of the shells and then top with a second shell, creating a sandwich.