3 Ingredient Rhubarb Squares

These simple 3 Ingredient Rhubarb Squares transform the tart, vibrant stalks of rhubarb into a delightful dessert with minimal effort. The contrast between the sweet cake topping and tangy rhubarb creates a perfect balance that makes these squares irresistibly delicious.

Why You’ll Love This Recipe

This recipe is the epitome of simplicity without sacrificing flavor. With only three ingredients, it’s perfect for beginners or when you need a quick dessert. The crumbly, buttery topping creates a delightful contrast to the soft, tangy rhubarb beneath. It’s an excellent way to use seasonal rhubarb when it’s abundant, and the dessert comes together in just minutes of hands-on time. These squares are versatile enough for casual family desserts or dressed up with a scoop of vanilla ice cream for guests.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

Rhubarb is the star of this dessert, providing a bright, tangy flavor that balances perfectly with the sweet topping. Fresh rhubarb works best, with its ruby-red stalks offering the most vibrant color and flavor, though frozen rhubarb can work in a pinch (just thaw and drain excess liquid first).

Vanilla cake mix serves as a convenient shortcut that creates a sweet, crumbly topping. The dry mix combines with butter to form a streusel-like layer that bakes into a golden crust. Don’t worry about preparing the cake according to package directions—we’re using it differently here.

Butter brings richness and helps bind the cake mix into perfect crumbles. When melted and mixed with the dry cake mix, it creates a texture that’s somewhere between a cookie and a cake. Unsalted butter is ideal, but salted works fine too—just expect a subtle sweet-savory contrast.

Directions

1. Preheat your oven to 350°F (175°C) to ensure it reaches the proper temperature before baking.
2. Take your 2 cups of chopped rhubarb and spread it evenly across the bottom of a baking dish. There’s no need to grease the dish first as the rhubarb will release moisture during baking.
3. In a separate bowl, combine the package of vanilla cake mix with 1/4 cup of melted butter. Stir until the mixture becomes crumbly in texture. It will not form a smooth batter.
4. Sprinkle this crumbly mixture evenly over the rhubarb layer, making sure to cover all the rhubarb for an even bake.
5. Place the dish in the preheated oven and bake for 40-45 minutes. You’ll know it’s done when the top turns a beautiful golden brown and the rhubarb underneath is tender when pierced with a fork.
6. Once baked, remove from the oven and allow the dessert to cool slightly before cutting into squares. This cooling time allows the dessert to set up properly for easier serving.

Servings and Timing

This recipe typically yields about 9-12 squares, depending on how you cut them. Preparation time is approximately 10 minutes, with a baking time of 40-45 minutes. Total time from start to finish is under an hour, making this an excellent option for last-minute dessert needs.

Variations

Fruit Combinations: Add strawberries, apples, or blueberries to the rhubarb for different flavor profiles. Strawberry-rhubarb is a classic combination that works beautifully in this recipe.

Cake Mix Flavors: Try different cake mix flavors such as lemon, strawberry, or spice cake for unique variations. Each brings its own character to the dessert.

Crunchy Topping: Add a 1/2 cup of chopped nuts like walnuts or pecans to the crumble topping for extra texture and flavor.

Spice it Up: Incorporate warming spices like cinnamon, nutmeg, or ginger into the crumble mixture for a cozy twist, especially nice in fall and winter.

Decadent Addition: Sprinkle white or dark chocolate chips over the top during the last 5 minutes of baking for a melty, sweet complement to the tart rhubarb.

Storage/Reheating

Room Temperature: These squares can be stored in an airtight container at room temperature for 1-2 days.

Refrigeration: For longer storage, keep them in the refrigerator for up to 5 days. The cool temperature helps maintain freshness, especially given the fruit content.

Freezing: These squares freeze exceptionally well. Place them in a single layer in an airtight container or freezer bag with parchment between layers to prevent sticking. They’ll keep for up to 3 months in the freezer.

Reheating: To reheat, place a square in the microwave for 20-30 seconds or warm in a 300°F oven for about 10 minutes until heated through. The squares are also delicious cold straight from the refrigerator.

FAQs

Can I use frozen rhubarb instead of fresh?

Yes, frozen rhubarb works well in this recipe. Thaw it first and drain any excess liquid to prevent your squares from becoming too soggy. You might need to adjust the baking time slightly as frozen rhubarb can release more moisture.

Do I need to prepare the cake mix according to package directions?

No, you’ll use the cake mix dry, straight from the box. It gets combined with melted butter to create a crumbly topping, not a traditional cake batter.

Can I make this recipe gluten-free?

Absolutely! Simply substitute the regular vanilla cake mix with a gluten-free vanilla cake mix. The rest of the recipe remains the same.

Should I peel the rhubarb before using it?

Peeling isn’t necessary unless the stalks are particularly tough or fibrous. Just trim the ends, remove any leaves (which are toxic), and chop the stalks into small pieces.

Why is my topping too dry or not crumbly enough?

If your topping seems too dry, you can add a bit more melted butter, one tablespoon at a time. If it’s not crumbly enough, you might have added too much butter, so incorporate a bit more dry cake mix.

Can I add other fruits to this recipe?

Yes! Strawberries, apples, or berries make excellent additions or substitutions. Keep the total amount of fruit at about 2 cups for best results.

How do I know when the squares are done baking?

The top should be golden brown, and when you insert a toothpick into the center (through to the rhubarb layer), the rhubarb should feel tender.

Can I double this recipe for a larger crowd?

Yes, this recipe doubles well. Use a larger baking dish or two separate dishes and increase the baking time by about 5-10 minutes, checking for doneness.

What size baking dish works best?

An 8×8 or 9×9-inch baking dish is ideal for this recipe. If using a different size, you may need to adjust the baking time accordingly.

Can I serve these squares with anything special?

These squares are wonderful on their own but truly shine when served warm with vanilla ice cream or whipped cream on top. A drizzle of caramel sauce is another delicious addition.

Conclusion

These 3 Ingredient Rhubarb Squares prove that outstanding desserts don’t require complicated techniques or lengthy ingredient lists. The beauty of this recipe lies in its simplicity and the wonderful contrast between the tart rhubarb and sweet, buttery topping. Whether you’re a novice baker looking for an easy win or an experienced cook seeking a quick dessert solution, these squares deliver impressive results with minimal effort. They’re perfect for showcasing seasonal rhubarb but can be enjoyed year-round with frozen rhubarb too. Give this recipe a try the next time you need a fuss-free dessert that’s sure to impress.

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