In a medium bowl, mix together 1 cup of all-purpose flour, 1/2 cup of granulated sugar, and 1 tablespoon of lemon zest. Cut in 1/4 cup of cold, cubed unsalted butter until the mixture resembles coarse crumbs. Refrigerate while you prepare the cake and filling.

In a mixing bowl, beat 8 ounces of softened cream cheese and 1/4 cup of granulated sugar until smooth and creamy. Add in 1 egg and 1 tablespoon of lemon juice, mixing well.

In a large bowl, whisk together 1 1/2 cups of all-purpose flour, 2 teaspoons of baking powder, and 1/2 teaspoon of salt. Cream together 1/2 cup of softened unsalted butter and 1 cup of granulated sugar until light and fluffy. Slowly beat in 1 egg and 2 tablespoons of lemon juice, alternating with the dry ingredients and 1/2 cup of milk.

Grease an 8-inch square baking pan. Spread half of the cake batter evenly in the bottom of the prepared pan. Dollop the cream cheese filling over the batter and then use the remaining batter to top it.

Sprinkle the prepared crumb topping evenly over the cake batter.

Preheat your oven to 350°F (175°C) and bake for 30 to 35 minutes or until the edges turn golden brown and a toothpick comes out clean.

Allow the cake to cool in the pan for about 15-20 minutes before slicing and serving either warm or at room temperature.