FOR THE MACARONS: 7 ounces confectioners' sugar 4 ounces almond flour 4 large egg whites, room temperature Pinch of cream of tartar 3 1/2 ounces superfine sugar Food coloring
Pulse confectioners' sugar and almond flour in a food processor until combined. Sift mixture 2 times. Preheat oven to 375 degrees (convection oven 325). Whisk whites with a mixer on medium speed until foamy. Add cream of tartar, and whisk until soft peaks form. Reduce speed to low, then add superfine granulated sugar. Increase speed to high, and whisk until stiff peaks form, about 8 minutes. Add food coloring and mix well. Sift flour mixture over whites, and fold until mixture is smooth and shiny. Transfer batter to a pastry bag fitted with a 1/2-inch plain round tip, and pipe 3/4-inch rounds 1 inch apart on parchment-lined baking sheets, dragging pastry tip to the side of rounds rather than forming peaks. Tap bottom of each sheet on work surface to release trapped air. Let stand at room temperature for at least 15 minutes. Bake 1 sheet at a time, rotating halfway through, until macarons are crisp and firm, about 10 minutes. Let macarons cool on sheets for 2 to 3 minutes, then transfer to a wire rack. (If macarons stick, spray water underneath parchment on hot sheet. The steam will help release macarons.) Sandwich 2 same-size macarons with 1 teaspoon filling. Serve immediately, or stack between layers of parchment, wrap in plastic, and freeze for up to 3 months.