Toast the flour in a non-stick skillet over medium heat, stirring constantly to prevent burning, until it turns light brown, about 5 minutes. Let cool, at least 15 minutes.
Cut waxed paper into twenty 4-inch squares.
Stir butter, sugar, powdered milk, and lemon extract into the flour. Mix well. Fill a polvoron mold tightly with a portion of the mixture. Press the plunger down to release the candy onto a square of waxed paper. Wrap candy in the waxed paper and twist the ends. Repeat until all of the candy mixture is used up.