I made a Raspberry Jam Crumb Cake today.
The topping did not come out very crumbly, and mostly blended into the cake, but it still tasted the same.
I swirled the raspberry jam into the cake batter in the pan, and used my fingers to sprinkle the topping batter over it. Because I mostly concentrated the crumbs in the middle, they clumped together and the edge was mostly cake.
This recipe was easy and fun to make. You can substitute any jam for the raspberry one, depending on what you like.
Here is the recipe.