Line 2 cookie sheets with parchment paper. Slice marzipan evenly into 6 (½-in.-thick) slices. Flatten each slice into a 2½-in. round; place on a prepared cookie sheet. Refrigerate until ready to assemble cookies.

For cookies, whisk together 1¾ cups plus 2 Tbsp. flour, baking powder, baking soda and salt in a medium bowl; set aside.

Beat butter in a large mixing bowl with an electric mixer on medium for 30 seconds. Add sugar, 2 tsp. lemon zest, 1 Tbsp. juice and vanilla. Beat until combined, scraping side of bowl occasionally. Beat in ricotta and egg until combined. Stir in flour mixture until combined. Cover and refrigerate dough for 1 hour or until firm.

Using lightly floured hands, shape dough into 12 balls. Flatten each ball into a 3-in.-round disk on the other prepared cookie sheet. Cover and freeze for 15 to 20 minutes.

Place oven rack in center of oven. Preheat oven to 350°. To assemble cookies, top 6 cookie dough disks with marzipan rounds. Then top with remaining cookie dough disks. Press edges to seal in marzipan; smooth any cracks in the dough. Place filled cookies 2 in. apart on the prepared cookie sheet.

Bake for 16 to 18 minutes or until edges of cookies begin to brown. Cool on cookie sheet for 4 minutes. Transfer cookies to a wire rack and cool completely.

For glaze, whisk together powdered sugar and remaining 2 Tbsp. lemon juice in a small bowl until smooth. Drizzle over the tops of cookies; sprinkle with sliced almonds. Garnish with additional lemon zest, if desired. Let stand until glaze is set. Store in an airtight container in the refrigerator up to 5 days. To soften centers of chilled cookies, microwave each cookie on HIGH for 10 to 15 seconds just before serving.