Preheat oven to 300°F degrees.

Use electric mixer to beat egg whites in a large bowl until foamy. Fold in almond meal, sugar almond extract and salt; cover and chill in the refrigerator for at least 2 hours or up to overnight.

Line two baking sheets with silicone mats or parchment paper. Place sliced almonds in a small bowl and press with the back of a spoon to break into smaller pieces.

Scoop 1 1/4 " balls of dough and shape into crescents (the sticky dough is easier to work with if your hands are damp). Roll each crescent in almonds (gently press almonds to dough if necessary), then place on baking sheets.

Bake until firm, about 22 minutes. Cool for 2 minutes on baking sheets, then transfer cookies to a wire rack to cool completely. Dust with powdered sugar before serving. Store in an airtight container at room temperature up to 3 days.

Yields 30 cookies.