Transfer mixture to a pastry bag fitted with a 1/2-inch plain tip (such as Ateco #806). Pipe mixture into marked circles on prepared baking sheets.
Pre-heat oven to 300°F. Allow the unbaked cookies to sit for 30 minutes to harden the tops while pre-heating.
Bake 20-25 minutes, rotating sheets halfway through, until macarons are slightly firm and can be gently lifted off parchment (bottoms will be dry). Let cool on sheets 5 minutes. Transfer macarons on parchment to a wire rack; let cool completely.
You can store the sandwiched macarons refrigerated in an airtight container for up to two weeks. They can also be frozen for longer.
Adapted from Martha Stewart's French Almond Macaron