Get the Recipe
As anyone who's eaten a pluot, owned a Labradoodle, or watched a Buffy-Angel crossover episode can tell you, hybrids are awesome. That holds especially true in Dessert Land, where the tradition of hybrids extends from ice-cream cakes to the more recent Cronut fever.
Hybrids were on my mind recently as I indulged in an afternoon blueberry crumb bar (one bonus to living in San Francisco: blueberries and blackberries are already at the markets!) It was tasty, but didn't quite hit the spot. The crumb topping tasted exactly like the base, and was it too sparse. I wanted big, buttery crumbs. I wanted notes of brown sugar. I wanted...a fruit crisp?
I know why the crumb bar tasted uniform. Most crumb bar recipes call for just one dough; it's split in half, with one part pressed into the pan and the other sprinkled over the fruit layer to make the "crumbs". That's how I've always made my crumb bars, and to be clear, there is nothing wrong with doing it that way. But why not bring crumb bars and crumbles together to get the best of both worlds?
Combining the two wasn't as easy as I thought. At first, my shortbread base wouldn't bake at the same rate as the topping. In a later iteration, my husband pointed out that the bars had too much base and not enough crumb. Finally, I came upon the results I was looking for: an easy shortbread cookie base covered with a layer of sweet blueberries and topped with an extra thick layer of buttery crumbs.
The base is essentially a soft shortbread cookie, just sturdy enough to hold the bars together without being hard or crisp. The topping turns golden brown, adding a sweet, lightly crunchy element. My secret ingredient? A thin layer of blueberry jam. It may not look like much, but don't leave it out: it really boosts the natural sweetness of the fresh blueberries. As the summer progresses, keep in mind that this recipe is versatile: simply swap out some or all of the blueberries for blackberries, raspberries, or a mix.