Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line it with parchment paper, leaving an overhang on both sides. This makes it easy to lift the loaf out cleanly once baked.

Step 2 — Mix the Dry Ingredients

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

Step 3 — Cream Butter, Sugar & Zest

In a large bowl, beat the softened butter and granulated sugar together on medium-high speed for 3 to 4 minutes, until light and fluffy. Add the lemon zest directly to the butter mixture and beat for one more minute. This step releases the essential lemon oils from the zest and is what makes the flavor so vibrant and aromatic.

Step 4 — Add the Wet Ingredients

Add the eggs one at a time, beating well after each addition. Then mix in the sour cream, vegetable oil, fresh lemon juice, lemon extract, and vanilla extract until fully combined. The batter may look slightly curdled at this stage — that is completely normal and will smooth out once the flour is added.

Step 5 — Combine

Add the dry ingredients to the wet ingredients in two additions, mixing on low speed just until no dry streaks remain. Do not overmix — this is what keeps the loaf tender and soft rather than dense and tough.

Step 6 — Bake

Pour the batter into the prepared loaf pan and smooth the top. Bake for 55 to 65 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs. If the top begins to brown too quickly, loosely tent it with aluminum foil after 40 minutes.

Step 7 — Cool Completely

Allow the loaf to cool in the pan on a wire rack for 30 minutes, then use the parchment overhang to lift it out. Let it cool completely on the rack before glazing — at least 1 hour. Do not rush this step. Glazing a warm loaf will cause the glaze to melt right off.

Step 8 — Make the Lemon Glaze

In a small bowl, whisk together the sifted powdered sugar, lemon juice, and heavy cream until smooth and pourable. If the glaze is too thick, add a few more drops of lemon juice. If it is too thin, add a little more powdered sugar.

Step 9 — Glaze & Serve

Pour the glaze evenly over the completely cooled loaf. For a thick, Starbucks-style coating, let the first layer set for 10 minutes and then apply a second coat. Allow the glaze to set for 15 to 20 minutes before slicing and serving.