Strawberry Rhubarb Crumble Bars

I think I’ve determined that the perfect picnic dessert is a bar cookie. Usually quick and easy to prepare, they slice up into conveniently-square-shaped bars that fit nicely into packing containers, plus they are generally sturdy and don’t need refrigeration, plates, or forks. So when I had a picnic to attend recently, I eyed my stash of frozen rhubarb and decided to make strawberry-rhubarb bars to bring along!

I admit that I made a few tweaks (both intentional and unintentional) to the recipe I found online, but I think they worked out just fine.

Like many of the recipe reviewers, I doubled the recipe and par-baked the crust for 10 minutes just to ensure that the bottoms of the bars were firm and sliceable– those were the intentional changes. Unintentionally, however, I put in 2 tablespoons of cornstarch instead of 2 teaspoons, which I worried would make the filling too chewy but which turned out fine. The bars held together well even when not refrigerated, and were really delicious.

I will note that in addition to making this recipe as bars, I also made another version, increasing the fruit by about 60%, to serve as a fruit crumble. It was also delicious (even though I made the same mistake with the cornstarch) and is equally amazing with vanilla ice cream (for dessert) or vanilla yogurt (for breakfast)!

Strawberry Rhubarb Crumble Bars (from Smitten Kitchen)

2 cups (160 grams) rolled oats/quick oats
1 3/4 cups (220 grams) extra all-purpose flour
1 cup (190 grams) brown sugar
1 tsp kosher salt
12 tablespoons (170 grams) unsalted butter, melted
2 teaspoons cornstarch
2 tablespoons (30 ml) lemon juice
2 tablespoons (30 grams) granulated sugar
2 cups (150 grams) small-diced rhubarb (from about 1 1/2 medium stalks)
2 cups (310 grams) small-diced strawberries

1. Preheat oven to 375 degrees F. Line a 9×13″ baking pan with foil or parchment paper.

2. In a bowl, combine oats, flour, brown sugar, and salt. Pour melted butter over the mixture and stir with a fork until no dry spots are left.

3. Reserving 1 cup of the oat mixture, press the remainder into the bottom of your lined pan.

4. Bake the crust for 10 minutes, then remove from oven.

5. Combine strawberries, rhubarb, sugar, lemon juice, and cornstarch in a bowl and spread over the top of the parbaked crust. Top with remaining oat mixture.

6. Bake 30-40 minutes, until fruit is bubbly and topping is toasty-smelling.