- With the rack in the middle position, preheat the oven to 375°F (190°C). Line two baking sheets with parchment paper (see note).
- In a food processor, pulse the almond powder and icing sugar until the texture of flour. Transfer to a bowl and set aside.
- Place the egg whites in another bowl. Set aside.
- In a small saucepan, bring the sugar and water to a boil. Let simmer until a candy thermometer reads 240°F (116°C). Remove from the heat.
- Beat the egg whites with an electric beater on medium speed until frothy. Drizzle the hot syrup onto the egg whites, avoiding the mixer’s beaters. Add the almond liqueur and extract. Beat continuously until stiff peaks form. With a spatula or whisk, gently fold in the dry ingredients.
- With a 2-tbsp (30 ml) ice cream scoop, shape 18 cookies onto each prepared baking sheet. With a fine sieve, dust the cookies with icing sugar.
- Bake one sheet at a time for 18 minutes or until the cookies just begin to brown and easily peel off the parchment paper. Let cool completely.
- The cookies will keep in an airtight container for 1 week at room temperature or 3 months in the freezer.
For this recipe, it is preferable to use parchment paper. Silicone mats tend to retain too much moisture during baking.