Lemon Cream Cheese Bars

Preheat oven to 350℉. Lightly grease a 9-inch square baking pan with cooking spray. Line with parchment paper, leaving a 2-inch overhang on all sides. Set aside. Gather all ingredients.

Stir together powdered sugar, 1 1/2 cups of the flour, and 3/4 teaspoon of the salt in a large bowl. Add butter and, using your hands, rub butter into flour mixture until it resembles coarse sand. Pour mixture into prepared baking pan, and press into an even layer on bottom. Chill, uncovered, in freezer for 5 minutes or refrigerator for 20 minutes, until cold.

Bake in preheated oven until slightly crisp and starting to turn golden brown, 20 to 25 minutes. Remove from oven, and let cool slightly while preparing filling, about 5 minutes. Decrease oven temperature to 325°F.

Beat granulated sugar and cream cheese with a stand mixer fitted with a paddle attachment on medium speed until smooth and fluffy, about 2 minutes. Add lemon juice, vanilla, and remaining 1/2 teaspoon salt, and beat on medium-low speed until smooth, scraping down sides of bowl as needed, about 1 minute. Add eggs and egg yolk, 1 at a time, beating on low until just combined after each addition. Add lemon zest and remaining 3 tablespoons flour; beat on low until incorporated, about 20 seconds. Pour over slightly cooled crust, and spread into an even layer.

Bake at 325°F until edges are set, top is matte, and center jiggles slightly as one mass, 40 to 45 minutes. Remove from oven and let cool completely in pan on a wire rack, 1 to 1 1/2 hours. Cover and refrigerate until completely chilled and set, at least 4 hours and up to overnight.

Remove bars from pan using parchment paper overhang. Place on a cutting board, and dust generously with powdered sugar. Top decoratively with lemon slices, and cut into 16 bars.