These are a variation on the classic Black and White Cookie. Black and white cookies are actually thin flat cakes that are popular at Jewish delis, and I've loved them since childhood because of how soft they are. The cookies themselves are typically flavored with vanilla as well as something tangy, like buttermilk or sour cream, and some lemon which brightens them up under their thick blankets of glaze. They have such great personality, and I love both sides equally.
For the cookies: Preheat the oven to 350 degrees F. Line 2 baking sheets with parchment paper and set aside.
In a medium bowl, sift together the flour, baking powder and salt and set aside. In a stand mixer fitted with a paddle attachment, mix together the butter, granulated sugar and lemon zest until light and fluffy, about 3 minutes. Add the eggs, one at a time, then add the vanilla. Add the yogurt and dry ingredients in 2 or 3 alternating additions and mix until just combined. Scoop out 1/4-cup blobs of the batter onto the lined baking sheets (using an ice cream scoop helps achieve uniform size and round cookies!), 2 to 3 inches apart. (You may need to bake in batches if they don't all fit on the two baking sheets.) Bake until the tops are set and the bottoms are just beginning to brown; begin checking for doneness at 14 minutes. Let cool on the pans for 5 minutes, then transfer to a wire rack to cool completely.
For the strawberry glaze: In a medium bowl, mix together the powdered sugar, strawberry powder, corn syrup, salt and 3 tablespoons yogurt until smooth and combined. If it's too thick to spread, add additional yogurt a little bit at a time until it's spreadable.
For the chocolate glaze: In a medium bowl, mix together the powdered sugar, cocoa powder, corn syrup, salt and 3 tablespoons yogurt until smooth and combined. If it's too thick to spread, add additional yogurt a little bit at a time until it's spreadable.
Spread half of each cookie on the flat side with a thick layer of strawberry glaze and let set, about 30 minutes. Spread the other half of each cookie with a thick layer of chocolate glaze and let set, about 30 minutes.