Position a rack in the middle of the oven. Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper and butter the paper.

Make the cookies: In a medium bowl, stir the flour, baking powder, baking soda, and salt together; set aside. In a large bowl, using an electric mixer on medium speed, beat the butter, sugar, and lemon zest until smooth and slightly lightened in color, about 1 minute. Stop the mixer and scrape the sides of the bowl as needed during mixing. Beat in the eggs, vanilla, and almond extract until blended, about 1 minute. On low speed, mix in half of the flour mixture just to incorporate it. Mix in the buttermilk, blending completely. Mix in the remaining flour mixture.

Using an ice cream scoop or measuring cup with a 1/4-cup capacity, scoop mounds of the dough onto the prepared baking sheet, spacing the cookies at least 2 1/2 inches apart. Bake the cookies until the edges and bottoms are lightly browned and a toothpick inserted in the center comes out dry, about 14 minutes. Cool the cookies on the baking sheet for 5 minutes, then use a wide metal spatula to transfer them to a wire rack to cool completely.

Make the chocolate glaze: In a medium saucepan, heat the cream, butter, and corn syrup over medium heat until the mixture is hot and the buffer melts; do not let boil. Remove the pan from the heat and add the chocolate chips. Let the chocolate melt for about 30 seconds, then stir until all of the chocolate has melted and the glaze is smooth. Let the glaze cool until it thickens enough to cling to the cookies, about 30 minutes.

Make the white glaze: When ready to glaze the cookies, in a medium bowl, stir the powdered sugar, 3 tablespoons of the hot water, corn syrup, and almond extract together to make a thick, smooth, pourable glaze. If necessary, continue adding hot water by the teaspoon to reach the desired consistency.

Turn the cookies so the flat bottom sides are up. Spoon about 1 tablespoon of the white glaze on one side of what is now the top of a cookie and use the back of the spoon to spread the glaze evenly over half of the cookie. (If the glaze thickens as you work so it does not spread easily, add a few drops of water.) Repeat with the remaining cookies. Spoon a generous 1 tablespoon of chocolate glaze over the bare half of each cookie, spreading it evenly over that half of the cookie. Some glaze may drip over the sides, and that is fine. (You will have about 3 tablespoons chocolate glaze left for another use.) Refrigerate the cookies to firm the glaze.

Wrap each cookie in plastic wrap and refrigerate. Serve cold or at room temperature. The cookies can be stored in the refrigerator for up to 3 days.