Preheat oven to 350°F (180°C). Spray an 8½ x 4½-inch loaf pan with baking spray with flour. Line pan with parchment paper, letting ends extend over sides of pan.
In a medium bowl, toss together berries and 1 tablespoon (8 grams) flour; set aside. 3. In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at time, beating well after each addition. Beat in vanilla bean paste and lemon zest.
In a medium bowl, whisk together remaining 1¼ cups (156 grams) flour, baking powder, and salt. With mixer on low speed, gradually add flour mixture to butter mixture alternately with sour cream, beginning and ending with flour mixture, beating just until combined after each addition. Gently fold in berry mixture. (Batter will be thick.) Spoon batter into prepared pan, spreading evenly.
Bake until a wooden pick inserted in center comes out clean, about 1 hour and 15 minutes. Let cool in pan for 15 minutes. Using excess parchment as handles, remove from pan, and let cool completely on a wire rack. Spread Sour Cream Vanilla Glaze onto cooled cake. Garnish with berries and mint, if desired.
Notes
Avoid using strawberries in this loaf, as they lose their color when baked and may leave wet spots in the cake crumb.
Recipe by Bake from Scratch at https://staging.bakefromscratch.com/vanilla-bean-berry-pound-cake-sour-cream-vanilla-glaze/