Sour Cream Coffee Cake

For Cake: Preheat oven to 350°F and grease bottom and sides of a 9x13 inch baking pan. In a medium bowl, carefully mix blueberries and lemon zest until combined. In a bowl of an electric mixer on medium-high speed, beat 1 stick butter until creamy, about 1 minute. Add 1 cup sugar and beat until light and fluffy, about 2 minutes. Add eggs, one at a time, beating well after each addition. Add vanilla extract and mix until thoroughly incorporated. Reduce speed to low, add flour mixture in thirds, alternating with sour cream and beginning and ending with flour, mixing until just incorporated. Carefully fold in blueberry-lemon mixture and spread batter evenly into prepared pan (batter will be stiff). For the Topping: In a small bowl, combine cinnamon and 2 Tbsp sugar, then sprinkle evenly over batter. Pour melted butter evenly over batter. Run a knife through the batter, to allow butter to sink into batter. Sprinkle batter with pecan. Bake until cake is browned and a fork inserted into center comes out clean, about 35 to 45 minutes. Remove from oven and transfer pan to a wire rack to cool. Serve warm or at room temperature.