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Delightful Rhubarb Dessert with Butter Sauce is the kind of cake that makes sense as soon as the first spoonful hits the plate. The rhubarb bakes into the crumb, leaving little tart pockets that keep the sweet cake from feeling heavy.
The warm butter sauce is simple but important. It is creamy, glossy, and rich enough to run down the sides of each square. Serve the cake still a little warm and the sauce soaks in just enough.
Rhubarb And Sauce Lineup
Choose rhubarb stalks that feel firm and crisp, with no limp ends. Deep red stalks look pretty, but greenish stalks bake just as well and often taste just as tart.
- Fresh rhubarb. Gives the cake its tart, juicy pockets and bright spring flavor.
- All-purpose flour. Builds a tender crumb sturdy enough to hold the fruit.
- Baking powder. Lifts the batter so the cake stays soft instead of heavy.
- Granulated sugar. Sweetens the cake and balances rhubarb's sharp edge.
- Unsalted butter. Adds richness to both the batter and the warm sauce.
- Egg. Helps the cake hold together cleanly when sliced.
- Whole milk. Keeps the crumb moist and helps the batter spread evenly.
- Vanilla extract. Rounds out the butter sauce and softens the tart fruit.
- Heavy cream. Turns the sauce glossy, smooth, and spoonable.
Bake It Until Just Set
- Prepare the pan. Heat the oven to 350°F and grease a 9-inch square baking pan so the edges release cleanly.
- Mix the dry ingredients. Whisk the flour, baking powder, and salt in a bowl to spread the leavening evenly.
- Cream the butter. Beat the softened butter and sugar until lighter and fluffy, then mix in the egg and vanilla.
- Finish the batter. Add the flour mixture in two additions, alternating with the milk, and stir only until combined.
- Fold in rhubarb. Gently fold in the chopped rhubarb and spread the thick batter into the pan.
- Bake and sauce. Bake until a toothpick comes out clean, then simmer the butter, sugar, cream, and vanilla into a smooth warm sauce.
Delightful Rhubarb Dessert Notes
The main thing to remember is that rhubarb brings water with it. Cut the stalks into small, even pieces so they soften before the cake dries out. Half-inch chunks are a good target. Bigger pieces can leave wet pockets near the center.
If you grow your own rhubarb, trim off and discard the leaves. The stalks are the part used for cooking. The University of Minnesota Extension rhubarb guide is a useful reference for harvesting and handling the plant safely.
This recipe is close in spirit to old farmhouse rhubarb cakes, including the classic Land O'Lakes rhubarb cake, but the batter here is a little richer and the sauce gets vanilla at the end for a softer finish.
The Sauce Needs Patience
Butter sauce looks simple because it is only butter, sugar, cream, and vanilla. Still, it rewards a slow hand. Heat it over medium and stir often until the sugar dissolves. Once it bubbles, give it a few more minutes so it thickens slightly and loses any grainy texture.
Do not boil it hard. A rolling boil can make the sauce greasy around the edges. If that happens, take it off the heat and whisk in a tablespoon of warm cream. It usually comes back together.
Spoon the sauce over cut pieces, not over the whole pan. That keeps leftover cake from getting soggy. If you love buttery desserts, the warm sauce idea also fits the cozy mood of Salted Caramel Kentucky Butter Cake.
Swaps That Taste Right
Fresh rhubarb gives the cleanest texture, but frozen works well when spring stalks are hard to find. If the rhubarb is very sour, add 2 extra tablespoons of sugar to the batter. If it is mild, keep the recipe as written so the dessert does not turn cloying.
You can add 1 teaspoon of orange zest to the batter. It brightens the fruit without making the cake taste citrusy. A pinch of cinnamon is good too, especially if you are serving this after a roast dinner or a Sunday meal.
For a creamier rhubarb bar instead of a spooned sauce dessert, try Rhubarb Bars with Cream Cheese. For a simpler fruit side to spoon over yogurt or pound cake, Sweet Roasted Rhubarb Vanilla is a lighter route.
Serving It Warm
This cake is best about 15 minutes after it leaves the oven. The crumb has had time to settle, but the rhubarb is still soft and steamy. Cut it with a thin knife and lift each square with a small spatula.
Pour the butter sauce while it is warm enough to flow. A little puddle on the plate is a good thing here. Vanilla ice cream melts into the sauce and turns it almost custardy, while unsweetened whipped cream keeps the dessert less rich.
If you are serving a rhubarb spread board or brunch table, add Easy Rhubarb Butter Spread beside biscuits or toast. The two recipes use rhubarb in very different ways, which makes the table feel planned without much extra work.
Storing The Cake Cleanly
Let the cake cool completely before covering it. Store it at room temperature for a day if your kitchen is cool, or refrigerate it for longer storage. The sauce should always go in the refrigerator because it contains cream.
To reheat, warm a slice in the microwave for 15-20 seconds or in a low oven until soft. Warm the sauce separately and stir before spooning it over the cake. If it has thickened too much in the fridge, add a small splash of cream while reheating.
The cake freezes better without sauce. Wrap cooled squares tightly and freeze for up to 2 months. Thaw overnight in the fridge, then warm and serve with freshly heated butter sauce.
Summary
A warm rhubarb cake with a creamy butter sauce, best served the day it is baked.
FAQs
- Can I use frozen rhubarb for this dessert?
Yes. Use frozen rhubarb straight from the freezer or thaw it briefly and drain off extra liquid. If the pieces are icy and clumped together, break them apart before folding them into the batter.
- Why is my rhubarb cake dense?
The batter was probably mixed too long after the flour went in. Stir just until the dry spots disappear, then fold in the rhubarb gently. A few small lumps are better than a tough cake.
- Can I make the butter sauce ahead?
Yes. Refrigerate the sauce for up to 4 days, then warm it slowly in a small saucepan. Whisk as it heats so the butter and cream come back together smoothly.
- What can I use instead of heavy cream?
Half-and-half works, but the sauce will be thinner. Evaporated milk also works in a pinch. Avoid low-fat milk because the sauce can taste flat and separate more easily.
- How should I store leftovers?
Store the cake covered at room temperature for 1 day or in the refrigerator for up to 4 days. Keep extra sauce in a separate covered jar. Warm individual slices gently before adding sauce.
- What should I serve with rhubarb dessert?
It is rich enough on its own, but vanilla ice cream is never wrong. Fresh strawberries or lightly sweetened whipped cream also work well with the tart rhubarb.
