Trace a 2-inch heart-shaped cookie cutter on parchment paper, spacing shapes about 2 inches apart. Place this under a second sheet of parchment for piping the shells or pipe free-hand without a template.

In a medium bowl, sift the powdered sugar, almond flour, and cocoa powder twice for a fine, lump-free mixture.

Heat the egg whites and granulated sugar over a double boiler until sugar dissolves and temperature reaches about 120°F. Transfer to a mixer bowl and whisk to soft peaks.

Add vanilla paste and red food gel, then whip to stiff peaks.

Gently fold ⅓ of the dry ingredients into the meringue using a silicone spatula until mostly combined. Add the rest and continue folding gently. When the batter flows smoothly in figure eights without breaking, it is ready.

Fill a piping bag fitted with a small round tip with batter. Pipe into heart shapes over the template, then carefully remove the template. Tap the baking sheet on the counter to release air bubbles.

Allow the piped shells to rest for 30-40 minutes at room temperature until a dry skin forms and batter does not stick when touched.

Preheat the oven to 300°F toward the end of the resting time. Bake macarons for about 12 minutes. Let cool completely before removing from parchment.

In a stand mixer bowl with a whisk attachment, combine cold heavy cream, granulated sugar, mascarpone, and vanilla paste. Whisk on low to combine, then increase to medium-high until thickened, about 30 seconds.

Transfer frosting to a piping bag with a small round tip. Pair macaron shells and pipe frosting onto the bottom shell of each pair. Sandwich the top shell gently to secure.