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Rhubarb Cupcakes

Course Dessert
Cuisine American
Keyword cupcakes, rhubarb
Prep Time 30 minutes
Cook Time 40 minutes
Servings 12 cupcakes

Ingredients

For the jam filling:

  • 4 cups (500 grams) rhubarb into ½” pieces
  • 1 cup (200 grams) granulated sugar
  • 1 1/2 tablespoons lemon juice (from about 1/2 medium lemon)
  • 1/2 tablespoon lemon zest (from about 1/2 medium lemon)
  • pinch of salt

For the cupcakes:

  • 1 cup (125 grams) all-purpose flour
  • cup (166 grams) granulated sugar
  • 1 teaspoon baking powder
  • 1/8 teaspoon salt
  • ½ cup (120 ml) milk
  • ¼ cup (60 ml) vegetable oil
  • 2 teaspoons vanilla extract
  • 1 large egg (50 grams, out of shell)
  • cup (80ml) hot water

For the frosting:

  • 1/4 cup (56 grams) unsalted butter, softened
  • 1 teaspoon vanilla extract
  • 1/2 cup of the above rhubarb jam
  • 2 cups (260 grams) powdered sugar
  • pinch of salt

Instructions

For the jam filling:

  • Put a large saucepan over medium heat and add in the rhubarb, sugar, lemon zest (but not the lemon juice) and salt.
  • Cook, stirring occasionally, for 8-10 minutes, or until the mixture has started to boil and thickens a bit.
  • Cover the saucepan with a lit and let it to simmer for 10 minutes, stirring occasionally, to thicken even more.
  • If the jam hasn’t thickened enough to coat the back of a spoon after 20 minutes, then stir in 2 teaspoons cornstarch and simmer for another 5 minutes (but not longer, as it might break down the whole mixture into a runny mess).
  • Once the jam has thickened, remove the pan from the heat and stir in the lemon juice.
  • Transfer the jam to a container (I prefer a wide one, so that jam cools quickly) and allow it to cool completely in the fridge (about 2-3 hours, depending on the size of your container).
  • While the jam is cooling, make the cupcakes.

For the cupcakes:

  • Preheat the oven to 350F and line a 12-cup muffin pan with liners.
  • In a large mixing bowl, whisk together the flour, sugar, baking powder and salt. Set aside.
  • In a small mixing bowl, whisk together the milk, vegetable oil, vanilla, egg, and water.
  • Add the wet mixture to the dry and stir until just combined. Do not overmix! The batter will be extremely thin!
  • Fill each muffin liner ½ full and bake for 15-17 minutes or until the tops turn golden brown and a toothpick inserted into the middle comes out clean.
  • Turn them out onto a cooling rack and let them completely cool before frosting.
  • Once the jam and cupcakes have completely cooled, prepare the frosting.

For the frosting:

  • Using a hand or stand mixer, beat together the butter, vanilla, ½ cup rhubarb jam and salt on medium speed until smooth.
  • On low speed, add in the powdered sugar gradually and mix until it becomes light, smooth and airy (about 3 minutes).
  • Use a 1 teaspoon measuring spoon to scoop out 1 teaspoon of cake from the center of each cupcake. Fill the hole with 1 teaspoon of rhubarb jam and cover the with the piece of cupcake that you removed.
  • Frost and serve. Refrigerate leftover in an airtight container for up to 3 days.