Line two large baking sheets with parchment paper. Put a master template under the parchment paper or draw about 12 1 1/2-inch circles in rows on the paper, about 1 inch apart.
Process powdered sugar and almond flour in a food processor until finely ground. Sift the mixture through a sieve. If there are more than 2 tablespoons of large chunks left in the sieve, grind them and sift again. Set the mixture aside.
In the bowl of a stand mixer fitter with a whisk attachment, beat egg whites at medium speed until frothy. Reduce the speed to low and gradually add the granulated sugar, 1 tablespoon at a time. Add vanilla. Increase the speed to high and beat until very stiff peaks form, about 5 minutes.
Sift the almond flour mixture over the egg whites. Using a rubber spatula, gently fold the almond flour mixture into the egg whites until the ingredients are just combined. Continue to fold the mixture until it has loosened and falls in a ribbon from the spatula.
Fit a pastry bag with a 1/2-inch round tip and fill the bag with the batter. Using the template as a guide, pipe circles onto the parchment papers.
Tap the bottom of each sheet on the work surface to release trapped air bubbles. Top with sprinkles. Let the cookies stand at room temperature for at least 30 minutes. This allows the cookies to develop their crusts.
Preheat oven to 325F. Bake the macarons for 10 to 12 minutes, until set but not browned.
Transfer the baking sheets to wire racks and let the macarons to cool completely on the pans. Once cooled, gently lift half of the cookies from the parchment paper and turn them upside down.
Spoon or pipe a teaspoon of filling onto each of the upside-down cookies. Top with the remaining cookies.