1-Preheat oven to 300°F (150°C). Line sheets with parchment.

2-First Step: Mise en Place Measure all ingredients accurately. Sift 100g almond flour with 100g powdered sugar twice. Discard lumps. This dry mix forms the base. Set aside two mixing bowls: one for dry, one heatproof for meringue. Room temperature egg whites whip best. Total prep: 10 minutes.

3-Second Step: Prepare Swiss Meringue Separate 100g egg whites. Place in heatproof bowl over simmering water (double boiler). Add 100g superfine sugar gradually, 1 tbsp at a time. Whisk constantly 7-10 minutes until 104-113°F (40-45°C). Rub between fingers; sugar should dissolve. Peaks turn stiff and glossy. Remove from heat. Whip on medium-high 5 minutes until cool, voluminous. Use candy thermometer for precision. This pasteurizes safely.

4-Third Step: Macaronage Add pinch salt and optional vanilla/color to meringue. Fold in dry mix in thirds. Use spatula; press batter against bowl sides. Continue until lava-like ribbon flows in figure-8. Test: batter smooths in 30 seconds. Avoid overmixing to prevent cracks. Takes 2-3 minutes.

5-Fourth Step: Piping and Resting Transfer to piping bag with round tip. Pipe 1.5-inch circles on parchment, 1-inch apart. Rap trays on counter 3-5 times to release air. Rest 30-60 minutes until skins form (dry touch). Humidity delays; use fan if needed. This crucial step ensures feet.

6-Fifth Step: Baking Bake one sheet at 300°F (150°C) middle rack 12-15 minutes. Rotate halfway. Feet ruffle up first 5 minutes. Shells lift clean when done. Cool fully on trays. No sticking if rested right.

7-Sixth Step: Filling and Assembly Beat 150g butter 2 minutes fluffy. Add 300g powdered sugar gradually, then cream and vanilla. Pipe onto one shell bottom. Sandwich gently. Mature 24 hours in fridge for best chew. Yields 30-40.

8-Final Step: Serving Bring to room temp 30 minutes before serving. Dust with powdered sugar. Pair with tea for party hosts. Store airtight. Troubleshooting: flat feet? Rest longer. Cracks? Oven too hot.