For the cakes:
- 1 1/4 cups plus 1 tablespoon all-purpose flour, divided
- 1 teaspoon baking powder
- 1/2 teaspoon salt
- 1/2 cup (1 stick) unsalted butter, softened
- 3/4 cup plus 1 tablespoon granulated sugar
- Zest of 1/2 lemon
- 2 eggs
- 1/4 teaspoon lemon extract
- A scant 1/2 cup (3 ounces) buttermilk
- 1 1/2 cups (8 ounces) chopped fresh rhubarb
For the glaze:
- 1 cup powdered sugar, plus more as needed
- 1 tablespoon lemon juice
- 1 tablespoon milk
- 3/4 tablespoon unsalted butter, melted
- Red food coloring (optional)
- Heat oven to 350 degrees F. Generously spray the bottom and sides of 4 1-cup mini bundt cake molds.
- In a large bowl, whisk together 1 1/4 cups flour, baking powder and salt.
- In a separate large bowl or bowl of a stand mixer fitted with the paddle attachment, cream butter, sugar and lemon zest 2 minutes until light and fluffy. Add eggs and lemon extract; stir to combine.
- Alternately stir flour mixture and buttermilk into the butter mixture, beginning and ending with the flour mixture and stirring well after each addition.
- Toss chopped rhubarb with remaining 1 tablespoon flour. Stir half of the rhubarb into the batter.
- Divide batter evenly among prepared mini bundt cake molds. Top evenly with remaining rhubarb.
- Bake cakes 20 to 25 minutes until golden brown on the edges and a toothpick inserted in the center comes out clean. Cool 15 minutes in pan, then carefully invert cakes from pan onto a cooling rack to cool completely.
- When cakes are fully cooled, combine glaze ingredients (add red food coloring if you want to dye the glaze pink), adding more powdered sugar as needed until glaze is smooth but thick. Pour glaze over cooled cakes.