Instructions

Adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 degrees. Line 2 baking sheets with parchment paper. Combine flour, baking soda, and salt in bowl.
Using stand mixer fitted with paddle, beat butter and granulated sugar on medium-high speed until pale and fluffy, about 2 minutes. Add 2 tablespoons milk, whole egg, and almond extract and beat until incorporated. Reduce speed to low, add flour mixture in 3 additions, and mix until just combined, scraping down bowl as needed.
Lightly beat egg white in bowl. Working on lightly floured counter, divide dough in half and form each into 4-inch disk. Roll each disk into 1/4-inch-thick circle. Using 2 1/2-inch cookie cutter, cut out rounds, gathering and rerolling dough as necessary. Transfer half of rounds to prepared sheets, 1 inch apart. Place heaping teaspoon of preserves in center of each round. Top with remaining rounds and crimp with fork. Brush filled rounds with beaten egg white and cut 1/2-inch X into center of each.
Bake until edges are lightly browned, 12 to 14 minutes, switching and rotating sheets halfway through baking. Let cookies cool on sheets for 5 minutes and then transfer to wire rack to cool completely, about 1 hour. Whisk confectioners’ sugar, remaining 2 tablespoons milk, and vanilla in bowl until smooth. Brush cookies with glaze and let sit for 30 minutes. Serve. (Tarts can be stored at room temperature for up to 2 days.)