Warm Rhubarb Cake with Butter Sauce (Air Fryer)
Intro
This Warm Rhubarb Cake with Butter Sauce is the perfect combination of tart and sweet. The rhubarb gives a fresh, slightly tangy burst, while the cake stays soft and fluffy. The magic happens when you pour the warm butter sauce over the top — it seeps into the cake, making each bite irresistibly moist and rich. The air fryer bakes it evenly without heating up your whole kitchen, making it ideal for quick dessert cravings or a special treat after dinner.
Preheat air fryer: 320°F (160°C) — 3 minutes
Bake cake: 320°F (160°C) — 28–32 minutes
Make butter sauce: 5 minutes on stovetop while cake bakes
Ingredients (Serves 6–8)
For the cake:
2 cups all-purpose flour
1 tsp baking soda
¼ tsp salt
1½ cups brown sugar
½ cup vegetable oil
1 cup buttermilk
1 large egg
1 tsp vanilla extract
2 cups diced rhubarb (fresh or frozen, thawed)
For the butter sauce:
1 cup granulated sugar
½ cup unsalted butter
½ cup heavy cream
1 tsp vanilla extract
Instructions
Make the Cake Batter
In a large mixing bowl, whisk together flour, baking soda, and salt.
In another bowl, whisk brown sugar, oil, buttermilk, egg, and vanilla until smooth.
Add wet ingredients to dry ingredients and stir until just combined.
Fold in diced rhubarb.
Air Fry the Cake
Lightly grease and flour your air fryer-safe cake pan.
Pour batter into the pan and spread evenly.
Place pan in preheated air fryer and bake at 320°F (160°C) for 28–32 minutes, or until a toothpick inserted in the center comes out clean.
Let it cool slightly in the pan while you make the sauce.
Make the Butter Sauce
In a small saucepan, combine sugar, butter, and cream.
Bring to a gentle boil over medium heat, stirring constantly.
Boil for 2–3 minutes until slightly thickened.
Remove from heat and stir in vanilla.
Serve Warm
Slice cake into wedges or squares.
Pour warm butter sauce generously over each slice.
Serve immediately — the sauce will soak in beautifully.
Air Fryer Pro Tip
If using frozen rhubarb, drain well after thawing to prevent extra moisture from making the cake dense.
If you’d like, I can also give you a cinnamon-sugar crumble topping version of this rhubarb cake that bakes right in the air fryer for extra texture and flavor. That would make it even more bakery-style.