Blueberry Coffee Cake (AKA Blueberry Boy Bait)

Name: Blueberry Coffee Cake (AKA Blueberry Boy Bait)
Prep time: 30 min
Cook time: 40 min
Total time: 1 h 10 min
Cuisine: American
Ingredients: 6 tablespoons (packed) light brown sugar; ½ cup all-purpose flour, (spooned into measuring cup and leveled-off); 1 teaspoon ground cinnamon; ¼ teaspoon salt; 4 tablespoons unsalted butter, (cold, cut into ½-inch (13-mm) chunks); 2 cups all-purpose flour, (spooned into measuring cup and leveled-off); 2 teaspoons baking powder; ½ teaspoon salt; 1/2 cup (1 stick) unsalted butter, softened; ¾ cup granulated sugar; 2 large eggs; 1½ teaspoons vanilla extract; 1 teaspoon (packed) lemon zest, (from 1 lemon); ½ cup milk; 2 cups fresh blueberries ((frozen may be used but do not defrost))