Lemon Blueberry Sour Cream Coffee Cake

By mariannefeldman

LEMON-BLUEBERRY SOUR CREAM COFFEE CAKE - CI
http://www.cooksillustrated.com/recipes/detail.asp?docid=5024

Published November 1, 2002.
Serves 12 to 16.
WHY THIS RECIPE WORKS:
We had two goals when developing our sour cream coffee cake recipe: We wanted a decadent, ultra-moist cake, pleasantly rich and dense from the addition of sour cream, and we had to have crisp, crunchy, melt-in-your-mouth streusel on the inside and on the top. A batter made with all-purpose flour (for structure), four eggs (for a tight crumb), plus plenty of butter, sour cream, and sugar gave our cake superior flavor and a velvety feel. As for the streusel, we found that a great one is made with nuts, brown sugar, plenty of cinnamon, and cold butter. To ensure that the cake cooked through completely, we baked it for a full hour at 350 degrees.

Refer to the illustrations below when layering the batter and streusel in the pan. A fixed-bottom, 10-inch tube pan (with 10-cup capacity) is best for this recipe. Note that the streusel is divided into two parts—one for the inner swirls, one for the topping.

Ingredients

• Streusel:
• INGREDIENTS
• 1 cup frozen blueberries
• 1 teaspoon grated lemon zest
• 3/4 cup unbleached all-purpose flour (3 3/4 ounces)
• 3/4 cup granulated sugar (5 1/4 ounces)
• 1/2 cup packed dark brown sugar (3 1/2 ounces)
• 2 tablespoons ground cinnamon
• 2 tablespoons unsalted butter , cold, cut into 2 pieces
• 1 cup pecans , chopped
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• Cake
• 12 tablespoons unsalted butter (1 1/2 sticks), softened but still cool, cut into 1/2-inch cubes
• 2 tablespoons butter , softened for greasing pan
• 4 large eggs
• 1 1/2 cups sour cream
• 1 tablespoon vanilla extract
• 2 1/4 cups unbleached all-purpose flour (11 1/2 ounces)
• 1 1/4 cups granulated sugar (8 3/4 ounces)
• 1 tablespoon baking powder
• 3/4 teaspoon baking soda
• 3/4 teaspoon table salt

Preparation

Step 1

INSTRUCTIONS
1. Toss blueberries with lemon zest in small bowl and set aside.

2. For the streusel: In food processor, process flour, granulated sugar, 1/4 cup dark brown sugar, and cinnamon until combined, about 15 seconds. Transfer 1 1/4 cups of flour/sugar mixture to small bowl; stir in remaining 1/4 cup brown sugar and set aside to use for streusel filling. Add butter and pecans to mixture in food processor; pulse until nuts and butter resemble small pebbly pieces, about ten 1-second pulses. Set aside to use as streusel topping.

3. For the cake: Adjust oven rack to lowest position and heat oven to 350 degrees. Grease 10-inch tube pan with 2 tablespoons softened butter. Whisk eggs, 1 cup sour cream, and vanilla in medium bowl until combined.

4. Combine flour, sugar, baking powder, baking soda, and salt in bowl of standing mixer; mix on low speed for 30 seconds to blend. Add butter and remaining 1/2 cup sour cream; mix on low speed until dry ingredients are moistened and mixture resembles wet sand, with few large butter pieces remaining, about 1 1/2 minutes. Increase to medium speed and beat until batter comes together, about 10 seconds; scrape down sides of bowl with rubber spatula. Lower speed to medium-low and gradually add egg mixture in 3 additions, beating for 20 seconds after each and scraping down sides of bowl. Increase speed to medium-high and beat until batter is light and fluffy, about 1 minute.

5. Using rubber spatula, spread 2 cups batter in bottom of prepared pan, smoothing surface. Sprinkle evenly with 1/2 cup blueberries. Sprinkle evenly with 3/4 cup streusel filling (without butter or nuts). Repeat with another 2 cups batter, remaining 1/2 cup blueberries, and remaining 3/4 cup streusel filling (without butter or nuts). Spread remaining batter over, then sprinkle with streusel topping (with butter and nuts).

6. Bake until cake feels firm to touch and long toothpick or skewer inserted into center comes out clean (bits of sugar from streusel may cling to tester), 50 to 60 minutes. Cool cake in pan on wire rack 30 minutes. Invert cake onto rimmed baking sheet (cake will be streusel-side down); remove tube pan, place wire rack on top of cake, and reinvert cake streusel-side up. Cool to room temperature, about 2 hours. Cut into wedges and serve. (Cake can be wrapped in foil and stored at room temperature for up to 5 days.)

STEP-BY-STEP
Layering the Batter and Streusel


1. Using rubber spatula, spread 2 cups batter in bottom of prepared pan, smoothing surface.


2. Sprinkle evenly with 3/4 cup streusel filling without butter or nuts.


3. Repeat steps 1 and 2 with 2 cups batter and remaining streusel without butter or nuts.


4. Spread remaining batter over, then sprinkle with streusel topping with butter and nuts.