Step 1: Prepare the Crumb Topping

1. In a small bowl, mix flour, brown sugar, granulated sugar, and cinnamon.
2. Pour in the melted butter and mix until crumbly.
3. Set aside while preparing the cake.

Step 2: Make the Cake Batter

1. Preheat your oven to 350°F (175°C) and grease a 9-inch baking pan.
2. In a medium bowl, whisk together flour, baking powder, baking soda, and salt.
3. In a separate bowl, beat butter and sugar until light and fluffy.
4. Add eggs one at a time, then mix in vanilla extract and sour cream.
5. Gradually add the dry ingredients, mixing until just combined.
6. Gently fold in the chopped strawberries.

Step 3: Assemble and Bake

1. Pour the batter into the prepared baking pan, spreading evenly.
2. Sprinkle the crumb topping generously over the batter.
3. Bake for 40-45 minutes or until a toothpick inserted in the center comes out clean.
4. Let the cake cool in the pan for 15 minutes before transferring to a wire rack.

Step 4: Make the Optional Glaze

1. In a small bowl, whisk together powdered sugar, milk, and vanilla extract.
2. Drizzle over the cooled cake before serving.