Marble Star Cookies

Prepare oven and baking sheets:

Preheat oven to 375°F. Line 3 baking sheets with parchment paper.

Combine butter and sugars:

Beat powdered sugar, butter, and granulated sugar with a stand mixer fitted with a paddle attachment on low speed just until combined, about 30 seconds. Increase speed to medium-low; beat until light and fluffy, 2 to 3 minutes, stopping to scrape down sides as needed. Beat in egg, vanilla bean paste, and almond extract until combined, 15 to 30 seconds.

Make dough:

Whisk together flour, baking powder, and salt in a medium bowl until combined. With mixer on low speed, gradually add flour mixture to butter mixture and beat just until dough comes together, about 2 minutes, stopping to scrape down sides as needed.

Divide dough, and add food coloring gel:

Turn out Dough onto a clean work surface, and divide into thirds. Reserve one-third plain dough. Place one-third of dough in a mixing bowl; add small amount of food coloring gel, beating on low speed until desired light blue color is reached, about 30 seconds. Transfer dough to a clean work surface. Place next third of dough in mixing bowl; add food coloring gel, increasing amount as desired, beating until desired deep blue color is reached, about 30 seconds.

Layer and arrange dough:

Divide each piece of dough in half to yield 6 portions total. Shape 1 plain dough portion into a 6-inch square on a sheet of parchment paper; shape 1 light blue dough portion into a 6-inch square, and place on top of plain dough square. Shape 1 deep blue dough portion into a 6-inch square; place on top of light blue square. Repeat layers once with remaining dough.

Fold stacked dough in half toward yourself, creating a taco-like shape.

Slice dough crosswise into quarters.

Turn quarters cut sides up; press dough quarters together, creating a swirled design.

Cut dough in half; shape each half into a disk, and wrap in plastic wrap. Chill in refrigerator for at least 30 minutes or up to 2 days.

Roll out dough:

Roll 1 dough disk between 2 sheets of parchment paper to 1/4-inch thickness. (If dough has been refrigerated for a long period, let stand at room temperature until slightly softened, 30 minutes to 1 hour.)

Cut out cookies:

Remove top piece of parchment paper. Cut dough using a very lightly floured 3- to 3 3/4-inch star cookie cutter; do not remove scraps. Transfer dough on parchment paper to a baking sheet, and freeze until firm, about 5 minutes. Place cut dough shapes at least 1 inch apart on prepared baking sheets. Reroll, cut, and chill dough scraps as needed. (Stars will become more blue than marbled with each reroll.) Sprinkle tops with sparkling sugar (if desired).

Bake cookies:

Bake in preheated oven, 1 pan at a time, until edges are set, 8 to 10 minutes. Let cool on pans 5 minutes; transfer cookies to wire rack, and let cool completely, 30 minutes to 1 hour. Store in an airtight container at room temperature for up to 5 days.