Step 1: Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan, or line with parchment paper, leaving an overhang on the long sides for easy removal.
Step 2: In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt. Set aside.
Step 3: In a separate medium bowl, combine the granulated sugar and lemon zest. Use your fingers to rub the zest into the sugar until fragrant. This helps release the lemon oils and intensifies the flavor.
Step 4: Add the softened unsalted butter to the lemon sugar mixture and beat with an electric mixer on medium speed until light and fluffy, about 2-3 minutes.
Step 5: Beat in the large eggs one at a time, ensuring each is fully incorporated before adding the next. Scrape down the sides of the bowl as needed.
Step 6: Stir in the full-fat Greek yogurt (or sour cream), fresh lemon juice, and vanilla extract until just combined. Be careful not to overmix.
Step 7: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined and no streaks of flour remain. Do not overmix.
Step 8: Pour the batter into the prepared loaf pan and spread evenly.
Step 9: Bake for 50-60 minutes, or until a wooden skewer inserted into the center comes out clean. If the top starts browning too quickly, you can loosely tent it with aluminum foil.
Step 10: Let the loaf cool in the pan on a wire rack for 10-15 minutes before carefully lifting it out using the parchment paper overhang. Allow it to cool completely on the wire rack before glazing.
Step 11: While the loaf cools, prepare the glaze. In a small bowl, whisk together the powdered sugar and 3 tablespoons of fresh lemon juice until smooth. If needed, add the remaining tablespoon of lemon juice for a pourable consistency.
Step 12: Once the loaf is completely cool, place it on a wire rack set over a baking sheet (to catch any drips). Pour the lemon glaze evenly over the top of the loaf, allowing it to drip down the sides.
Step 13: Let the glaze set for at least 15-20 minutes before slicing and serving. Enjoy your homemade Starbucks lemon loaf recipe!