SERVINGS: 16 servings
Preheat the oven to 375 F. Spray a 9-inch square baking tin with nonstick spray. Line with parchment paper so there is overhang on two sides.
Add the topping ingredients to a stand mixer with the paddle attachment. Beat until combined and crumbly. Transfer to another bowl and squeeze mixture by hand to form a clumpy mixture. Set aside in the freezer.
Add the sugar and butter to the stand mixer and beat until combined. Beat in the egg. Add the milk, sour cream, and vanilla and beat until combined.
Whisk together the flour, baking powder, and salt in a medium bowl. Sift the flour mixture into the stand mixer bowl. Turn the mixer on low and mix until just combined.
Add the cherries and mix by hand. Pour the batter into the baking tin and top with the topping mixture.
Bake for 45 minutes until golden. Let cool in the pan for 10 minutes. Lift out of the pan using the parchment and cut into squares. Serve warm or at room temperature.