In a medium bowl, combine 1/2 cup of all-purpose flour, 1/4 cup of granulated sugar, and the zest of one medium lemon. Cut in 3 tablespoons of cold unsalted butter until the mixture resembles coarse crumbs. Chill the topping while preparing the batter.

In a mixing bowl, beat 8 ounces of softened cream cheese with 1/4 cup of granulated sugar until smooth. Add in 1 large egg and 3 tablespoons of lemon juice, mixing until fully incorporated.

Preheat your oven to 350°F (175°C). In a large bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking powder, and 1/2 teaspoon of salt. In another bowl, cream together 1/2 cup of softened unsalted butter with 1/2 cup of granulated sugar until fluffy. Add the remaining egg and 3-4 tablespoons of lemon juice. Mix dry ingredients alternately with 3/4 cup of milk.

Grease an 8-inch square baking pan. Spread half of the batter evenly, spoon the cream cheese filling on top, dollop the remaining batter over, and gently spread to cover.

Sprinkle the crumb topping over the batter and bake for 30 to 35 minutes until edges are golden. Let it cool slightly before serving.