01 -
Shake powdered sugar and almond flour through a fine sieve together into a bowl to remove lumps. Once done, set it aside.
02 -
In a clean bowl, beat egg whites using a mixer. Begin on low speed, then gradually increase. As soft peaks appear, sprinkle in granulated sugar slowly. Keep whisking until stiff peaks develop.
03 -
Gently fold the almond flour and sugar mix into the whipped egg whites. Stir while adding food coloring if using. Stop folding when the batter drips off your spatula like lava would.
04 -
Pour the batter into a piping bag fitted with a round tip. On parchment-lined sheets, make heart shapes by drawing a small 'V.' Keep sizes similar so they bake evenly.
05 -
Let the piped batter sit out for about 30-60 minutes to dry. Touch them gently; they shouldn't feel sticky, which means they've formed the proper skin.
06 -
Preheat your oven to 300°F (150°C). After resting, bake the shells for 18-20 minutes. They should feel solid and easily lift from the paper.
07 -
Beat softened butter in a bowl until smooth. Add powdered sugar, mixing one spoonful at a time. Stir in vanilla and salt. Mix in cream or milk—add the food coloring here if you'd like color.
08 -
Once shells are cool, flip them over. Apply some buttercream on the flat side of one shell and stick another on top to make a sandwich.
09 -
Seal the sandwiches in an airtight container and refrigerate for at least 24 hours. This helps the filling soften the shells for a better bite.