Sift together almond meal, powdered sugar and salt in a large bowl.
With a stand or hand mixer, whip egg whites on high until frothy, about 1 minute. Gradually add granulated sugar and extract. Continue whipping on high for 3-5 more minutes until stiff peaks form.
Scoop egg whites into flour mixture and gently fold together with rubber spatula until just incorporated. Divide batter into two and pour into separate bowls.
Dye one batch red and fold with spatula until batter just barely runs in a continuous ribbon off the spatula. Do not overmix! Leave the second batch undyed, but fold with the spatula until the same consistency.
Pour red batter into one side of a piping bag fitted with a 1/2” round tip and the white batter into the opposite side, trying to keep them as separate as possible. Pipe 1” circles onto a parchment-lined or silicone mat-lined sheet. Let dry for 45 minutes-1 hour before baking.
Bake at 350, one sheet at a time, for 14 minutes. Rotate sheet hallway through baking. They are done if you press down gently on them and they don’t smoosh down at all. Allow to cool completely on the baking sheet.
Buttercream filling: Whip butter with a stand or hand mixer for about 5 minutes. Slowly incorporate powdered sugar by the spoonful. Add in remaining ingredients and whip for an additional minute. Place into a piping bag fitted with a round tip and pipe in between two macaron shells, forming a sandwich.
Place macarons in the freezer for at least 30 minutes before dipping in chocolate.
Chocolate: Microwave 6 oz of the chocolate at 50% power until mostly, but not completely melted. Add in remaining chocolate and microwave at 50% in 5 second increments until completely melted.
Dip macarons in chocolate and immediately cover in sprinkles before chocolate hardens. Allow chocolate to harden completely at room temperature or in the fridge before serving.