1⅓ cups (267 grams) granulated sugar3 large eggs (150 grams), room temperature2½ teaspoons (5 grams) lime zest⅔ cup (149 grams) vegetable oil½ cup (120 grams) sour cream, room temperature1 teaspoon (4 grams) vanilla extract2½ cups (313 grams) plus 1 tablespoon (8 grams) all-purpose flour, divided2 teaspoons (10 grams) baking powder1 teaspoon (3 grams) kosher salt6 ounces (170 grams) fresh blueberries, dividedBlueberry-Lime Buttercream (recipe follows)Garnish: fresh blueberries
Preheat oven to 350°F (180°C). Spray an 8½x4½-inch loaf pan with baking spray with flour; line pan with parchment paper, letting excess extend over all sides of pan.
In a large bowl, whisk together sugar, eggs, and lime zest until light and fluffy, about 2 minutes. Stir in oil, sour cream, and vanilla until well combined.
In medium bowl, whisk together 2½ cups (313 grams) flour, baking powder, and salt.
In a small bowl, toss together 4 ounces (113 grams) blueberries and remaining 1 tablespoon (8 grams) flour until blueberries are well coated.
In another small bowl, mash remaining 2 ounces (57 grams) blueberries with a fork.
Using a rubber spatula, fold flour mixture into sugar mixture until just until combined. Fold in all blueberries. Spoon batter into prepared pan, and spread smooth with a small offset spatula.
Bake for 40 minutes. Loosely cover with foil, and bake until a wooden pick inserted in center comes out clean, 35 to 45 minutes more. Let cool in pan for 10 minutes. Using excess parchment as handles, remove from pan, and let cool completely on a wire rack.
Spread Blueberry-Lime Buttercream onto loaf. Garnish with blueberries, if desired. Store in airtight container for up to 3 days.