Lemon Poppy Seed Cupcakes with Blackberry Frosting
These Lemon Poppy Seed Cupcakes with Blackberry Frosting are bright, zesty, and bursting with fresh flavor. A tender lemon poppy seed sponge is topped with a naturally purple blackberry buttercream made from a real fruit reduction—no artificial coloring required. Perfect for spring celebrations, brunches, and special occasions.
Equipment
- Cupcake Pan
- Saucepan
- Fine-mesh sieve
- Electric mixer
Ingredients
- 1 ½ cups all-purpose flour
- 1 cup granulated sugar
- 1 ½ tsp baking powder
- ¼ tsp salt
- 1 Tbsp poppy seeds
- ½ cup unsalted butter, melted and cooled
- 1 large egg, room temperature
- ½ cup sour cream or full-fat Greek yogurt
- ¼ cup whole milk
- 1 tsp vanilla extract
- 2 Tbsp fresh lemon juice
- 1 Tbsp lemon zest
- 1 cup fresh or frozen blackberries
- 1 cup unsalted butter, softened (for frosting)
- 3–4 cups powdered sugar, sifted
- 1 tsp vanilla extract (for frosting)
- 1 pinch salt
Instructions
- Cook blackberries in a small saucepan over medium heat for 8–10 minutes, mashing as they soften. Strain through a fine-mesh sieve to remove seeds. Return juice to pan and simmer until reduced to 2–3 tablespoons of thick syrup. Cool completely.
- Preheat oven to 350°F (175°C) and line a muffin tin. In a large bowl, whisk together flour, sugar, baking powder, salt, and poppy seeds.
- In a separate bowl, whisk together melted butter, egg, sour cream, milk, vanilla, lemon juice, and lemon zest until smooth.
- Fold wet ingredients into dry ingredients until just combined. Fill liners ⅔ full and bake for 18–22 minutes, until a toothpick comes out clean. Cool completely.
- Beat butter until pale and creamy. Gradually add powdered sugar, cooled blackberry reduction, vanilla, and salt. Beat on high for 3–5 minutes until light and fluffy.
- Pipe frosting onto cooled cupcakes. Garnish with fresh blackberries or mint if desired.
Notes
The blackberry frosting gets its color and flavor from a concentrated reduction. Cupcakes can be stored in the refrigerator for up to 3 days; bring to room temperature before serving for best texture.