Moist Vanilla Cupcakes with Vanilla Buttercream

Adam GALLAGHER
2026-02-20T02:30:00-05:00

Perfectly moist vanilla cupcakes made with sour cream for a tender, bakery-style crumb — topped with a silky vanilla buttercream frosting. Makes 12 cupcakes.
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Why These Cupcakes Work

The secret to an exceptionally moist vanilla cupcake is sour cream. It adds fat and acidity, tenderizing the crumb and keeping the cupcakes soft for days. An extra egg yolk deepens the richness, giving the crumb a softer, more velvety texture that sits firmly in bakery-style territory. The result is a tight, plush crumb with clean, forward vanilla flavour. It’s the kind of cupcake that holds its texture from the first bite to the last — no dryness, no crumble.

Cupcake Ingredients

1½ cups (190g) all-purpose flour

1½ tsp baking powder

½ tsp fine sea salt

½ cup (115g) unsalted butter, room temperature

1 cup (200g) granulated sugar

2 large eggs + 1 egg yolk, room temperature

2 tsp pure vanilla extract

¼ cup (60ml) whole milk, room temperature

½ cup (120g) full-fat sour cream, room temperature (added last)

Vanilla Buttercream Ingredients

1 cup (225g) unsalted butter, room temperature

3–3½ cups (360–420g) icing sugar, sifted

2–3 tbsp heavy cream or whole milk

2 tsp pure vanilla extract

Pinch of fine sea salt

Instructions

Cupcakes

1. Preheat oven to 350°F (175°C). Line a standard 12-cup muffin tin with paper liners.

2. In a medium bowl, whisk together flour, baking powder, and salt. Set aside.

3. In a large bowl, beat butter and sugar with a hand or stand mixer on medium-high speed for 3–4 minutes until pale and fluffy.

4. Add eggs and yolk one at a time, beating well after each addition. Mix in vanilla extract.

5. Reduce speed to low. Add the flour mixture in two additions, alternating with the milk, beginning and ending with flour. Mix until just combined — do not overmix.

6. Fold in the sour cream until smooth. The batter may look slightly curdled at first — keep mixing until fully smooth.

7. Divide the batter evenly among the 12 liners, filling each about two-thirds full.

8. Bake for 18–22 minutes. The cupcakes are done when the edges are light golden, the centre springs back when lightly touched, and a toothpick inserted in the centre comes out clean. For precision, an internal temperature of 200–205°F (93–96°C) confirms a fully baked crumb.

9. Cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before frosting.

Vanilla Buttercream

1. Beat butter on medium-high speed for 3–4 minutes until very pale and fluffy.

2. Reduce speed to low and gradually add sifted icing sugar, one cup at a time. Use 3 cups for a softer, less sweet buttercream ideal for spreading; use 3½ cups for a firmer consistency that holds its shape when piped.

3. Add vanilla extract, a pinch of salt, and 2 tablespoons of cream. Increase speed to medium-high and beat for 2 minutes until light and smooth. Add more cream as needed to reach your desired consistency.

4. Transfer to a piping bag fitted with your preferred tip and frost cooled cupcakes.

Tips & Variations

Sour cream substitutes: Full-fat Greek yogurt works 1:1 and produces a nearly identical result. A neutral oil (like avocado or sunflower) can replace the butter at a 3:4 ratio for an even moister crumb.

Room temperature ingredients: Critical for a smooth, emulsified batter. Cold butter or eggs will cause the batter to curdle.

Don’t overmix: Once the flour is added, mix only until the streaks disappear. The sour cream is folded in last to keep the emulsion tight and reduce the risk of overdeveloping the gluten.

Storage: Store frosted cupcakes in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days. Bring to room temperature before serving.