Preheat the Oven

Preheat your oven to 350°F (175°C).

Grease and flour a 9-inch round cake pan, or line it with parchment paper for easy removal.

Mix Dry Ingredients

In a medium bowl, whisk together:

2 cups all-purpose flour

1 ½ teaspoons baking powder

1⁄2 teaspoon baking soda

1⁄4 teaspoon salt

Set aside.

Cream Butter and Sugar

In a large mixing bowl, beat 1 cup softened butter and 1 ½ cups sugar using a hand or stand mixer on medium-high speed until light and fluffy (about 3–5 minutes).

Add Eggs and Vanilla

Add the eggs one at a time, mixing well after each addition.

Stir in 1 teaspoon vanilla extract.

Add Wet and Dry Ingredients

Gradually add the dry flour mixture to the wet mixture, alternating with the sour cream or buttermilk, beginning and ending with the flour.

Mix until just combined—don’t overmix.

Create the Strawberry Swirl

Reserve about 1/4 cup of the cake batter in a small bowl.

Stir in the 1 cup strawberry puree to that reserved batter.

Pour the plain batter into the prepared pan, then spoon the strawberry batter over the top.

Use a knife or skewer to gently swirl the pink mixture into the vanilla batter for a marbled effect.

Bake

Smooth the top and place the pan into the preheated oven.

Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Make the Glaze

In a small bowl, whisk together:

1⁄2 cup powdered sugar

2 tablespoons fresh strawberry puree

1 teaspoon milk (add a little more if needed for pouring consistency)

Mix until smooth and glossy.

Glaze the Cake

Once the cake is completely cool, drizzle the glaze generously over the top.

Let it set for a few minutes before slicing.