Plums are that perfect transitional fruit that feels like Fall is on the horizon while still being a summer staple. After coming off a weekend where the heat index was about 104F every day, the brisk 86F felt like a change in seasons. While I'm not ready for apple butter everything just yet, It was the perfect excuse to enjoy some plum crumble bars.
The Key Layers in Plum Crumble Bars
Shortbread Crust
The beauty of shortbread is how easy it is to make. There are only four real ingredients:
- Flour
- Butter
- Powdered sugar
- Flavoring
For my ratio, I use a 1:2:4 method. 1 part powdered sugar: 2 parts butter: 4 parts flour.
In a recipe that might break down as ½ cup powdered sugar, 1 cup butter, 2 cups flour. But, knowing the ratio, you can make as small (or large) of a batch of shortbread as you'd like.
So, if you're looking at these photos and think the shortbread crust is too thick for your personal taste, you could easily cut it in half using the 1:2:4 ratio!
Homemade Plum Jam
Jam is one of those things that used to scare me. It feels like it should be so hard to make, but it's actually one of the easiest things to play around with in the kitchen.
The trick to making sure you're making jam and not just a plum sauce is putting a plate in your freezer. The plate gets super cold, and you're able to test if your jam is setting up or not. I personally like a super thick jam, so I flip the plate upside down to ensure it's thick enough. If it doesn't drip off, it's ready to be pulled off the heat!
Crumble Topping
Good streusel reminds me of making a good biscuit. You need patience to work the butter in. If you over work the butter, you will be left with more of a cookie batter than a streusel. While that's fine, it's not necessarily what you're going for here.
Add in your butter slowly and carefully and stop just as it begins to form sand-like clumps.
If you're not comfortable using a food processor, you can also use two forks to cut the butter in. Or, I also like to just use my hands, pressing the butter between my fingers until it's throughout the mixture.
I hope you enjoy this recipe! If you make it, give it a rating and comment below! Would love to hear if y'all enjoyed it!
With love and butter--Kristi
Plum Crumble Bars
Ingredients
Shortbread Crust
- 1 cup butter
- ½ cup powdered sugar
- 2 cups flour
Plum Jam
- 8 medium plums
- 4 tablespoon granulated sugar
Streusel Crumble
- ½ cup instant oats or steel cut
- ⅓ cup brown sugar
- ⅓ cup flour
- ½ teaspoon salt
- ¼ cup cold unsalted butter cubed
Instructions
- Preheat oven to 375°F. In a stand mixer, cream together butter and sugar until fully combined. Slowly add in our until just combined. Press into bottom of lined 8×8" cake pan. Using a fork, poke shallow holes across the dough to help prevent uneven rising. Bake for 20 minutes.1 cup butter, ½ cup powdered sugar, 2 cups flour
- While shortbread bakes, peel, de-pit, and dice plums. Place in a medium sauce pot with sugar. Place a plate in the freezer to test your mixture later. Place sauce pot over medium-low heat, stirring occasionally. After about 8 minutes, the mixture will begin to thicken. Once it coats the spatula, take the plate out of freezer and put a dollop of jam on plate. If it sets, it is ready to be removed from heat and set aside. If it runs o , place plate back in freezer and continue to cook for another 3-5 minutes.8 medium plums, 4 tablespoon granulated sugar
- When shortbread is done baking, prepare your crumble. In a stand mixer, combine dry ingredients; stir with paddle attachment. Add butter. Put mixer on low and watch carefully as the mixture begins to combine. When it just begins to get clumpy, stop the mixer. if not, it will full incorporate the our into the butter. Set mixture aside.½ cup instant oats, ⅓ cup brown sugar, ⅓ cup flour, ½ teaspoon salt, ¼ cup cold unsalted butter
- Spread the plum jam on top of shortbread in a thin, even layer. Sprinkle crumble mixture evenly across jam layer. Bake at 375F for 25-30 minutes, until the crumble begins to turn a golden brown.