Preheat oven to 300°F (150°C). Line tray with parchment or silicone mat. Drink something caffeinated while you're at it.
Sift almond flour and powdered sugar together. Toss out clumps like toxic exes.
Whip aquafaba and cream of tartar until soft peaks form—channel your inner meringue sorceress.
Slowly add granulated sugar and beat until glossy stiff peaks happen. Fold in espresso powder.
Gently fold dry mix into meringue. Mix until the batter flows like lava, not soup.
Pipe 1-inch circles onto tray. Tap tray like you're mad at it—gets out air bubbles.
Let sit 30–40 minutes until tops look dry and matte. (Yes, this is your patience test.)
Bake for 20 minutes. Cool completely before even thinking about filling.
For the cream, beat vegan butter, sugar, coffee mix, vanilla, and salt until smooth and ready to seduce.
Pipe filling onto half the shells. Top with the rest. Do a victory dance.
Chill for 24 hours if you want perfect texture. Or eat immediately if self-control is a myth.