Prepare a 13 inch x 9 inch pan by greasing the sides then pouring the melted butter into the bottom.
Arrange those delicious strawberries on the brown sugar.
Now sprinkle evenly with rhubarb.
Press those beautiful strawberries and rhubarb gently into the brown sugar.
Cream your butter and sugars together, then whip in the eggs and vanilla until the mixture is light and fluffy.
Whisk together your dry ingredients.
Alternating between the dry mixture and sour cream, add them into the butter mixture with your mixer on low speed.
Add in two cups of chopped rhubarb that has been dusted in flour, to help it not sink. Gently mix it in.
Gently spread the batter over top of the strawberry/rhubarb mixture.
Bake in a 350 degree oven for 35-40 minutes, until it's golden brown and a knife inserted comes out clean.