Here is a detailed, step-by-step Sour Cream Blueberry Coffee Cake recipe with full instructions, pan shape guidance, texture cues, and baking tips.

Sour Cream Blueberry Coffee Cake

Pan Shape: 9-inch round cake pan (2-inch deep)
Alternative: 8-inch square pan (for slightly thicker cake)
Yield: 8–10 slices

Texture & Structure

Soft, moist crumb from sour cream
Tender, buttery base
Juicy blueberry pockets throughout
Thick cinnamon streusel layer in the center and on top
Golden brown, slightly domed surface

Ingredients

For the Streusel (Crumb Topping & Filling)

1 cup (125 g) all-purpose flour
1/2 cup (100 g) granulated sugar
1/2 cup (100 g) light brown sugar, packed
1 teaspoon ground cinnamon
1/4 teaspoon salt
1/2 cup (115 g) unsalted butter, melted

Texture goal: Moist, sandy clumps that hold when squeezed.

For the Cake Batter

2 cups (250 g) all-purpose flour
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1/2 cup (115 g) unsalted butter, softened (room temperature)
1 cup (200 g) granulated sugar
2 large eggs, room temperature
1 teaspoon pure vanilla extract
1 cup (240 g) full-fat sour cream (room temperature)
2 cups (300 g) fresh blueberries
(If using frozen, do NOT thaw.)

Optional: 1 tablespoon flour to toss blueberries (prevents sinking)

Equipment

9-inch round cake pan
Parchment paper (cut into a circle for bottom)
Hand or stand mixer
Two mixing bowls
Rubber spatula
Wire cooling rack

Step-by-Step Instructions

Step 1: Prepare the Pan

Preheat oven to 350°F (175°C).
Grease the cake pan with butter or nonstick spray.
Line the bottom with parchment paper.
Lightly grease the parchment.

This ensures clean release and clean slice edges.

Step 2: Make the Streusel

In a medium bowl, combine flour, granulated sugar, brown sugar, cinnamon, and salt.
Pour melted butter over the mixture.
Mix with a fork until crumbly clumps form.

The mixture should look like coarse wet sand and form chunks when pressed.

Set aside.

Step 3: Prepare Dry Ingredients

In a separate bowl, whisk together:

Flour
Baking powder
Baking soda
Salt

Whisking evenly distributes leavening agents for even rise.

Step 4: Cream Butter and Sugar

In a large bowl, beat softened butter on medium speed until smooth (about 1 minute).
Add sugar.
Beat 2–3 minutes until light and fluffy.

Visual cue: Mixture becomes pale and slightly airy.

Step 5: Add Eggs and Vanilla

Add eggs one at a time.
Beat well after each addition.
Mix in vanilla.

Scrape down sides of bowl to ensure even mixing.

Step 6: Add Sour Cream

Add sour cream.
Mix on low speed just until combined.

The batter will look thick and creamy.

Step 7: Add Dry Ingredients

Add dry mixture gradually.
Mix on low just until incorporated.
Do NOT overmix (prevents dense cake).

The batter should be thick but spreadable.

Step 8: Prepare Blueberries

If using fresh:

Gently fold blueberries into batter.

If using frozen:

Toss in 1 tablespoon flour first.
Fold in gently without thawing.

Assembly (Layered Structure)

This cake has a layered crumb design.

Step 9: First Batter Layer

Spread half of the batter evenly in the prepared pan.
Use a spatula to smooth the surface.

Layer thickness: About 1 inch.

Step 10: Middle Streusel Layer

Sprinkle half of the streusel evenly over batter.
Do not press down.

Step 11: Top Batter Layer

Carefully spoon remaining batter over streusel.
Gently spread to edges without disturbing crumb layer.

Tip: Drop spoonfuls around surface first, then smooth.

Step 12: Final Streusel Top

Sprinkle remaining streusel evenly on top.
Lightly press a few larger clumps for texture.

Baking

Bake at 350°F (175°C) for 50–60 minutes.
Check at 50 minutes.

Doneness test:

Insert toothpick in center.
It should come out clean or with a few moist crumbs (no wet batter).

Top should be:

Golden brown
Slightly domed
Crumb crisp and set

If browning too quickly:

Tent loosely with foil during last 15 minutes.

Cooling

Let cake cool in pan for 20 minutes.
Run knife around edges.
Remove from pan.
Cool completely on wire rack.

Cooling prevents crumb from breaking when sliced.

Optional Glaze (Light Drizzle)

Mix:

1 cup powdered sugar
1–2 tablespoons milk
1/2 teaspoon vanilla

Drizzle in thin lines over cooled cake.

Serving Shape & Appearance

Round cake with visible blueberry pockets.
Thick crumb topping on surface.
Interior shows three layers: cake – streusel – cake.
Slice into wedges (like pie).

Storage

Room Temperature:

Cover tightly.
Keeps 2 days.

Refrigerator:

Up to 5 days.
Bring to room temperature before serving.

Freezing:

Wrap slices individually.
Freeze up to 2 months.

Texture Summary

Interior:

Very moist
Tender crumb
Slight density from sour cream

Top:

Crunchy cinnamon crumble

Flavor:

Sweet but balanced
Slight tang from sour cream
Bursts of juicy blueberry

Sour cream blueberry coffee cake