Make rhubarb oatmeal bars for a sweet and tart treat featuring spring’s first fruits!

With a hearty oat crust and tart but sweet rhubarb filling, these rhubarb crumble bars have something for everyone.

Simple to bake and a delight to eat these old-fashioned rhubarb bars are ideal for weeknight dessert, potlucks, and more.

If you have homemade canned rhubarb pie filling in your pantry or freezer, these bars are an ideal way to use up a quart. If you don’t, there’s a recipe for homemade filling included below.

Staple Ingredients

The great thing about this recipe is that once you have rhubarb harvested from the garden or purchased from the farmer’s market, you likely already have all the other ingredients on hand making it quick to pull together. Here are a few tips to keep in mind.

Self-Rising Flour

The crust uses self-rising flour for ease. It provides plenty of lift to the crust without making it too puffy and keeping a slight crunch.

If you don’t have self-rising flour, make your own by mixing together 1 1/2 cups all purpose flour, 2 1/4 teaspoons baking powder and a generous 1/4 teaspoon of salt. That will work in the same fashion for you.

Oats

Use rolled oats for a heartier texture in the crust. Quick or instant could likely work but won’t have the same bite to them.

Brown Sugar

The brown sugar in the crust provides for a great depth of flavor in contrast to the filling. I’ve made the bars with both light and dark brown types – even a combination when I didn’t have a full cup of dark brown sugar on hand. Use whatever you have in the pantry or prefer.

Rhubarb

For the filling, you will need 3 full cups chopped rhubarb. Dice it small for a smoother filling, a larger chop will keep some chunks in the bars.

Save a bit of time, if desired, dice the rhubarb the day before and keep stored in an airtight container in the refrigerator.

When ready to bake, just pull the rhubarb from the fridge and proceed with the recipe.

Substitute Canned Pie Filling

While you can make the filling fresh in spring, if rhubarb season has passed use a quart jar of frozen or canned rhubarb pie filling instead.

Using Frozen Rhubarb

If you have slices of frozen rhubarb in the freezer, let it thaw and drain the excess water. Then proceed with cooking the filling as described in the recipe below.

Other Options

Use any pie filling you have on hand, strawberry rhubarb would be quite nice. Homemade jam would also work but provide slightly different texture.

After spreading the filling on the crust, top it with some chocolate or white chocolate chips. Then finish by crumbling on the top crust and bake.

Add up to 1/2 cup finely chopped nuts to the crust for more crunch and flavor.

Drizzle the baked and cooled bars with some melted chocolate.

A simple vanilla powdered sugar glaze, drizzled over the baked bars is lovely and tasty, too!

How to Serve

There’s no real reason to get fancy here. This is intentionally a rustic, old-fashioned dessert designed to highlight the garden harvest. Keep it simple:

Cut the bars with a sharp knife and serve with coffee or tea as desired for a light snack or even brunch.

Add a dollop of whipped cream or scoop of ice cream for an even more over-the-top dessert.

Dust the cut and plated bars with just a bit of powdered sugar right before serving for added color and eye-catching appeal.

How to Store

Keep leftovers in an airtight container in the refrigerator for up to 5 days.

For longer term storage, freeze the bars. Simply cut the bars and put into freezer bags and freeze solid.

Let frozen bars thaw in the refrigerator prior to serving. Eat up frozen bars within six months for optimum freshness and flavor.

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