Prepare the Oven and Pan: Set your oven to 350°F (177°C) and lightly grease a standard 9×5-inch loaf pan with nonstick spray or butter. This will ensure your bread releases easily after baking.
Combine Dry Ingredients: In a large mixing bowl, whisk together the flour, poppy seeds, baking soda, baking powder, and salt until evenly mixed. This ensures your leavening agents and flavorings are well distributed.
Mix Wet Ingredients: In a separate medium bowl, beat the egg and granulated sugar together until smooth and slightly thickened. Then add the vegetable oil, sour cream, whole milk, lemon juice, and lemon zest. Stir gently until the mixture is homogenous.
Bring Batter Together: Pour the wet mixture into the dry ingredients bowl. Using a spatula or whisk, fold gently until just combined. Some small lumps are fine—overmixing can make the bread tough.
Transfer to Pan and Bake: Spread the batter evenly in your prepared loaf pan. Bake for about 50 to 60 minutes, checking around the 50-minute mark. If the bread starts browning too fast, loosely cover with foil to prevent over-browning. Insert a toothpick into the center; when it comes out clean or with a few moist crumbs, the bread is done.
Cool Completely: Place the loaf pan on a wire rack and allow the bread to cool fully in the pan. This resting period helps the bread set and makes slicing easier.
Prepare and Apply Glaze: In a small bowl, whisk together the powdered sugar and lemon juice until smooth. While the bread is still warm, drizzle the glaze over the top so it seeps in, adding extra moisture and tang. Garnish with candied lemon slices if desired.
Serve or Store: Once glazed and cooled, slice the bread to serve. Store leftovers at room temperature for up to 2 days, or refrigerate for up to one week in an airtight container.