These Easy Old Fashioned 5-Ingredient Oatmeal Rhubarb Bars are a nostalgic treat with a perfect balance of sweet, tart, and buttery crunch. After testing countless vintage recipes, I’ve perfected this simplified version that delivers all the classic flavor with minimal fuss. The method I use ensures the rhubarb softens beautifully without making the crust soggy, creating a dessert that’s both rustic and utterly satisfying.

Easy Old Fashioned 5-Ingredient Oatmeal Rhubarb Bars

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Author: Dorothy Miller

Ingredients

Scale

1 cup oatmeal (rolled oats or quick oats)
¾ cup all purpose flour
½ cup brown sugar
7 tablespoons salted butter (melted)
2 cups rhubarb (sliced in ½ inch pieces)

Instructions

Preheat oven to 350º
In a mixing bowl, combine oats, flour, and brown sugar.
Pour in melted butter and stir until evenly distributed, and crumbly.

Press ⅔ of oat and flour mixture into an 8×8 inch baking pan.
Spread rhubarb evenly over the top and then sprinkle last ⅓ of oat crumble over the top.

Bake in the center of the oven for about 30 minutes, or until the top begins to brown, and the rhubarb is cooked through.
Let cool at least 15 minutes before serving. Serve warm or cold

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Easy Old Fashioned 5-Ingredient Oatmeal Rhubarb Bars Recipe