If you've read my other instructables you might notice I have a thing for blueberries, I just love 'em. When the Ohio summer blueberry crop comes in I use as many as I can fresh, and freeze the remainder for use the rest of the year. You can use fresh or frozen in this delicious snacking cake. To combat the usual problem of blueberries sinking in cakes, Cook's Illustrated decided to make a basic blueberry jam to swirl throughout the batter, not only does this keep the cake wonderfully moist, but it helps get blueberry flavor in every bite. The minute I read about that method, I knew I wanted to bake this cake, I love recipes that you instantly know will be a hit.

Some buttermilk lends tanginess, and lemon zest and juice brighten the flavors and compliment the blueberries so well. Possibly my favorite part of the cake is a lemon glaze, you don't HAVE to glaze the cake, but a lemony burst of flavor is always welcome on my tongue! This is really an all-season cake, light enough after summer dinner, or comforting enough for a wintertime snack with a warm drink.

I hope you'll try this marbled blueberry bundt cake soon, enjoy!

Serves 12

Recipe from Cook's Illustrated, May 2013.

Step 1: Gather Ingredients

You'll need:

FOR THE CAKE:

3 cups (15 ounces) all-purpose flour
1 1/2 teaspoons baking powder
3/4 teaspoon baking soda
1 teaspoon salt
1/2 teaspoon ground cinnamon
3/4 cup buttermilk
2 teaspoons grated lemon zest plus 3 tablespoons juice
2 teaspoons vanilla extract
3 large eggs plus 1 large yolk, room temperature
18 tablespoons (2 1/4 sticks) unsalted butter, softened
2 cups (14 ounces) sugar

FOR THE FILLING:

3/4 cup (5 1/4 ounces) sugar
3 tablespoons low- or no-sugar-needed fruit pectin (do NOT use regular pectin)
Pinch salt
10 ounces (2 cups) fresh or thawed frozen blueberries
1 teaspoon grated lemon zest plus 1 tablespoons juice

FOR THE GLAZE:

3 - 4 tablespoons lemon juice (2 lemons)
2 cups (8 ounces) confectioners' sugar

Step 2: Prepare Batter

Adjust oven rack to lower-middle position and heat oven to 325 degrees F.

Heavily spray 12-cup nonstick Bundt pan with baking spray with flour. (Spray the pan well to prevent sticking. If you don’t have nonstick baking spray with flour, mix 1 tablespoon melted butter and 1 tablespoon flour into a paste and brush inside the pan.)

Whisk flour, baking powder, baking soda, salt, and cinnamon together in large bowl. Whisk buttermilk, lemon zest and juice, and vanilla together in medium bowl. Gently whisk eggs and yolk to combine in third bowl.

Using stand mixer fitted with paddle, beat butter and sugar on medium-high speed until pale and fluffy, about 3 minutes, scraping down bowl as needed. Reduce speed to medium and beat in half of eggs until incorporated, about 15 seconds. Repeat with remaining eggs, scraping down bowl after incorporating.

Reduce speed to low and add one-third of flour mixture, followed by half of buttermilk mixture, mixing until just incorporated after each addition, about 5 seconds. Repeat using half of remaining flour mixture and all of remaining buttermilk mixture. Scrape down bowl, add remaining flour mixture, and mix at medium-low speed until batter is thoroughly combined, about 15 seconds.

Remove bowl from mixer and fold batter once or twice with rubber spatula to incorporate any remaining flour. Cover bowl with plastic wrap and set aside while preparing filling (batter will inflate a bit).

Step 3: Prepare Filling

Whisk sugar, pectin, and salt together in small saucepan.

Process blueberries in blender until mostly smooth, about 1 minute. Transfer 1/4 cup puree and lemon zest to saucepan with sugar mixture and stir to thoroughly combine. Heat sugar-blueberry mixture over medium heat until just simmering, about 3 minutes, stirring frequently to dissolve sugar and pectin.

Transfer mixture to medium bowl and let cool for 5 minutes. Add remaining puree and lemon juice to cooled mixture and whisk to combine. Let sit until slightly set, about 8 minutes.

Step 4: Bake

Spoon half of batter into prepared pan and smooth top. Using back of spoon, create 1/2-inch-deep channel in center of batter. Spoon half of filling into channel. Using butter knife or small offset spatula, thoroughly swirl filling into batter (there should be no large pockets of filling remaining). Repeat swirling step with remaining batter and filling.

Bake until top is golden brown and skewer inserted in center comes out with no crumbs attached, 60 to 70 minutes. Let cake cool in pan on wire rack for 10 minutes, then invert cake directly onto wire rack.

If you are glazing the cake, continue to next step, if leaving unglazed, let cake cool for at least 3 hours before serving.

Step 5: Glaze, Cool, and Enjoy

While cake is baking, whisk together 3 tablespoons lemon juice and sugar until smooth, gradually adding more lemon juice as needed until glaze is thick but still pourable (mixture should leave faint trail across bottom of mixing bowl when drizzled from whisk).

After cake has been removed from pan and inverted onto wire rack set in baking sheet, pour half of glaze over warm cake and let cool for 1 hour.

Pour remaining glaze evenly over cake and continue to let cool to room temperature, at least 2 hours. Serve and enjoy.

Covered, the finished cake can be stored at room temperature for up to 3 days.