Spray an 8x8 baking pan with nonstick spray and set aside.
In a small bowl add the 1 Tablespoon of flour to the strawberries and rhubarb and gently stir to coat fruit with flour. Set aside.
In a medium bowl whisk together the 2 cups of flour, baking powder, and salt. (whisking will remove any lumps in the flour). Set aside.
In a large bowl cream together the sugar, ¼ cup butter and egg on medium-high speed with a hand held mixer for 1-2 minutes. Add the ½ cup milk and mix on low speed until smooth, 1-2 minutes.
Next add the dry ingredients and stir just until mixed.
Gently stir in the flour-coated fruit.
Spread mixture evenly into the prepared pan.
In a small bowl mix together with a fork the topping ingredients of brown sugar, 3 Tablespoons of flour and 3 Tablespoons of butter until it is crumbly. Sprinkle on top of the cake batter.
Bake for 35-40 minutes or until the cake tester comes out with just a few crumbs on it. Let it sit in the pan for 10 minutes before serving.
For glaze whisk together in a small bowl the powdered sugar, 1 tablespoon milk and vanilla. Drizzle over the cooled cake.
Notes
Tips:
To Store: Store your cake at room temperature, either uncovered or very loosely covered for a few days. You can also place them in an airtight container in the refrigerator for about 3-5 days.
To Freeze: To freeze, wrap the cake tightly in plastic wrap and then in foil. Place in the freezer for up to 6 months.
Storage:
Use room temperature butter. This will help you get a smooth base to your cake
The egg will mix into your cake better if it is at room temperature.
I recommend chopping your strawberries very small. If the berries are not chopped small, they can potentially create too much moisture in the cake.
You can line the bottom of your cake pan with parchment paper to prevent the cake from sticking.