• In the bowl of a stand mixer fitted with the paddle attachment, beat butter and granulated sugar at medium speed until creamy, 3 to 4 minutes, stopping to scrape sides of bowl. Add Marzipan, and beat until well combined. Beat in egg yolks and vanilla bean paste.
• In a medium bowl, sift together flour and salt. With mixer on low speed, add flour mixture to butter mixture in two additions, beating until combined after each addition.
• Turn out dough, and divide in half. Shape each half into a disk. Wrap in plastic wrap, and refrigerate for 30 minutes or up to overnight. (If refrigerating overnight, let dough stand at room temperature for about 15 minutes before rolling.)
• Preheat oven to 325°F (170°C). Line baking sheets with parchment paper.
• Between 2 sheets of parchment paper, roll half of dough to ½-inch thickness. Using a 2¼-inch fluted round cutter dipped in flour, cut dough, and place 1 inch apart on prepared pans. Using your thumb or the back of a spoon, create a 1-inch-wide indentation in center of each cookie. Repeat procedure with remaining dough, re-rolling scraps to use all dough. Freeze until firm, about 10 minutes.
• Bake until bottoms are lightly browned, 18 to 24 minutes. Let cool on pans for 5 minutes. Remove from pans, and let cool completely on wire racks.
• Spoon White Chocolate Ganache in center of each cooled cookie. Garnish with sparkling sugars, if desired Let stand until ganache is set, about 1 hour. Store in an airtight container for up to 4 days.

Marzipan:

• In the work bowl of a food processor, pulse flour and confectioners' sugar until combined. Add egg white and extracts; process until mixture holds together when pressed between fingers. (If mixture is too dry, add water, 1 teaspoon [5 grams] at a time, processing after each addition.) Wrap tightly in plastic wrap, and refrigerate for up to 1 month.

White Chocolate Ganache:

• In a medium microwave-safe bowl, heat cream on high just until steaming, about 30 seconds. Add white chocolate; let stand for 5 minutes. Whisk until chocolate is melted and mixture is smooth. Use immediately.