Sift together the almond flour and powdered sugar in a large bowl and set aside.

In a separate bowl, beat the egg whites until foamy, then add the cream of tartar and continue beating until soft peaks form.

Gradually add the granulated sugar while continuing to beat until stiff peaks form, then mix in the vanilla extract.

Gently fold the almond flour mixture into the egg whites in three additions, being careful not to deflate the batter.

Divide the batter into three bowls: leave one plain, add red gel food coloring to the second, and blue gel food coloring to the third. Mix until well incorporated.

Line baking sheets with parchment paper and transfer each colored batter into separate piping bags fitted with round tips.

Pipe 1.5-inch circles onto the prepared baking sheets, leaving space between each macaron, and tap the sheets to release air bubbles.

Let the macarons sit at room temperature for 30-60 minutes until a skin forms on the surface.

Preheat the oven to 300°F and bake the macarons for 15-20 minutes, rotating the sheets halfway through.

Allow the macarons to cool completely on the baking sheets.

For the filling, beat the softened butter until creamy, then gradually add the powdered sugar and mix until well combined.

Add the vanilla extract and heavy cream, mixing until smooth.

Pair the macaron shells and pipe a generous amount of filling onto the flat side of half of the shells, then top with the remaining shells to create sandwiches.

Refrigerate the macarons for at least 24 hours to allow the flavors to meld.