Aunt Helen swears by this 4 ingredient classic. I never believed her until I watched an entire pan disappear at the potluck.

This is the kind of pan I bring to church suppers when I know folks will be circling the dessert table more than once. Aunt Helen has been making these 4-ingredient rhubarb dream bars since the 1960s, right here in the Midwest, when every farmhouse had a rhubarb patch out back and butter on the counter. For years she swore you didn’t need eggs or fancy extras—just rhubarb, sugar, flour, and butter—and I’ll admit, I raised an eyebrow. Then I watched an entire glass dish of these bars vanish at a potluck before I could even snag a second piece. The tender crumb crust, glossy sweet-tart rhubarb layer, and buttery crumble on top taste like the kind of simple magic only an old family recipe can give you.

Serve these rhubarb dream bars slightly warm or at room temperature, cut into neat squares right in the glass casserole dish. They go especially well with a small scoop of vanilla ice cream or a dollop of lightly sweetened whipped cream, though they’re lovely all on their own with a cup of coffee or hot tea. For a true Midwestern potluck spread, set them out alongside a simple ham dinner, potato salad, and a green salad, then let everyone help themselves as they wander back through the kitchen for “just a sliver more.”

Servings: 12

2 cups all-purpose flour, divided

Preheat your oven to 350°F (175°C). Lightly butter or spray a 9×13-inch glass casserole dish so the bars release easily after baking.

In a medium mixing bowl, combine 1 1/2 cups of the flour and 1/2 cup of the sugar. Add the cold, cubed butter.

Using a pastry cutter, two knives, or your fingertips, cut the butter into the flour-sugar mixture until it looks like coarse crumbs with some pea-sized bits of butter remaining. This will be your crust and topping.

Measure out about 1 1/2 cups of this crumb mixture and set it aside in a small bowl for the topping.

Pour the remaining crumb mixture into the prepared glass casserole dish. Press it firmly and evenly across the bottom to form a crust, making sure there are no bare spots.

Bake the crust in the preheated oven for 12–15 minutes, or until it is just starting to look set and very lightly golden around the edges. Remove from the oven and set aside while you prepare the filling