In a food processor, place flour & butter & pulse to combine until mixture resembles coarse crumbs. Place mixture in a large bowl. Add ground almonds, 1/4 cup powdered sugar, 1 pkg vanilla sugar, salt & extract. Knead dough with your hands in bowl until it comes together, about 5 minutes. Divide dough into four equal pieces, shaping each into a ball. Wrap in plastic wrap place in a sealed plastic bag. Refrigerate for at least 30 minutes or up to 2 days.