Name: Razzleberry Rhubarb Bars
Prep time: 60 min
Cook time: 30 min
Total time: 90 min
Ingredients: 1 3/4 cups all-purpose flour; 1 cup old-fashioned oats; 1/2 cup chopped pecans; ¾ cup brown sugar; 1 teaspoon baking powder; 1 1/2 teaspoons cinnamon; ½ teaspoon salt; 13 Tablespoons unsalted butter, (softened and sliced into tablespoons); 1 cup rhubarb, (cut into half-inch pieces); 1 cup raspberries, (fresh or frozen); 1 cup blackberries, (fresh or frozen); 1/2 cup granulated sugar; 2 Tablespoons cornstarch; Pinch of salt; 2 Tablespoons freshly-squeezed lemon juice; 2 teaspoons lemon zest

A lusciously jammy filling of raspberries, blackberries and rhubarb paired with a buttery, brown sugary crumble crust and topping!

Rhubarb season is in full swing and berry season is just beginning, so why not combine two of nature’s treasures into one incredible treat?

Today, we’re pairing sweet blackberries with juicy raspberries and tart rhubarb to create one of the most scrumptious bars of the summer…

Why You’ll Love These Razzleberry Rhubarb Bars

Perfect Balance of Sweet and Tart: The combination of blackberries, raspberries, and rhubarb creates the perfect balance of sweetness and tartness. This filling also pairs incredibly well with the buttery, brown sugary crust and topping.

Quick and Easy Treat: These bars can be thrown together in less than an hour, which is great for those days when you feel like something sweet but don’t want to spend hours in the kitchen.

Simple Ingredients: These bars are made of ingredients that you most likely already have in your pantry.

Great for Gatherings: With summer upon us, these bars would be perfect to bring to potlucks, cookouts, bbq’s, etc. You can make them ahead of time, and the recipe doubles easily!

Ingredient Notes

Rhubarb: I used fresh rhubarb from my garden, but you can also find it in the grocery store during the spring and summer months. Look for stalks that are firm and crisp without any soft spots. The color doesn’t matter too much since they all taste pretty similar whether the stalks are bright red, pink, or green. If you don’t have access to fresh, you can use frozen. Just make sure to thaw it out completely and drain any excess liquid before using in the recipe.

Raspberries and Blackberries: You can use fresh or frozen berries. It makes no difference at all since you’ll be pre-cooking the filling before pouring it onto the crust and baking.

Cornstarch: This ingredient is my thickener of choice when it comes to any kind of fruit filling. It has double the thickening power of flour and it produces a clearer, glossier filling. It also has a neutral taste, unlike flour.

White Granulated Sugar: I like the cleaner, brighter flavor that white sugar brings to the berry-rhubarb filling. You can use brown sugar, but it will result in a caramel-like flavor. Brown sugar also provides more moisture due to the molasses, so be sure to increase the thickener by a teaspoon to prevent runny filling.

Fresh Lemon: Both lemon juice and lemon zest help to brighten the flavor and balance out the sweetness with its zesty acidity. It also helps to thicken the filling by boosting the natural pectin.

Old-Fashioned Rolled Oats: I prefer using rolled oats over quick oats since they lend a nice and chewy texture to the crumble. Quick oats will work in a pinch, but they’re much finer, so the result is softer and more cake-like in texture. Definitely stay away from instant oats, which will cause the bars to be mushy.

Brown Sugar: When it comes to crumbles, brown sugar is your best bet. Not only does it provide a deeper, caramelized, and more complex flavor than white sugar, but its moist, soft texture allows it to clump up properly to form that nice crumbly topping.

Pecans: I love adding pecans to crumbles or streusels because they add the perfect crunch and toasty nutty flavor. You can also use walnuts, if you prefer.

Cinnamon: This warm and aromatic spice adds extra depth to the crumble, pairing perfectly with the brown sugar, oats, and pecans.

Why This Recipe Works

Pre-Cooking the Filling: This step results in a perfectly thickened and jammy filling. It’s a guarantee that you won’t end up with runny or soupy filling and also ensures a crust that isn’t soggy. What you end up with is lusciously thick filling, a crisp crust, and peace of mind knowing that when you slice into these bars, the filling doesn’t run all over the place.

Par-Baking the Crust: Along with pre-cooking the filling, par-baking the crust prevents the crust from becoming mushy or soggy. It also ensures that the bottom crust bakes all the way through, resulting in a crisp crust that contrasts well with the soft berry-rhubarb filling.

Allowing Bars to Cool Completely: This step is absolutely vital for ensuring those nice clean cuts. If you don’t want filling to run everywhere, make sure to wait until the bars have cooled at least 4 hours. I actually allowed mine to sit overnight. If you want to speed up the process, allow the bars to cool at room temperature for an hour, then place them in the refrigerator for another hour, or until they’ve cooled completely.

Can I double the recipe?

Yes, this recipe doubles very easily! Simply double all of the ingredients and bake everything in a 9×13-inch baking dish instead of an 8-inch square dish. Baking time will vary, so I would start checking the bars at 30 minutes during the final baking stage.