Preheat the oven to 350°F. Spray a 9x5-inch loaf pan with baking spray.
In a large bowl, combine the sugar and lemon zest, rubbing them together with your hands to release the oils in the lemon zest. Add the eggs and whisk or beat with an electric mixer until thick.
1 cup (200g) granulated sugar, 2 Tablespoons lemon zest, 3 large eggs
Stir in the sour cream, butter, oil, lemon juice, lemon extract, and vanilla.
1 cup sour cream , 1/4 cup salted butter, 1/4 cup canola oil, 2 Tablespoons lemon juice, 1 Tablespoon lemon extract, 1 teaspoon vanilla extract
Add the dry ingredients, stirring just until barely combined. Do not overmix.
1 2/3 cups (235g) all-purpose flour, 1 teaspoons baking powder, 1/4 teaspoon baking soda, 1/2 teaspoon salt
Pour the batter into the prepared pan. Run a spatula down the middle of the loaf to create the split effect on the top. Bake for 45-55 minutes or until a tester inserted into the center of the loaf comes out clean with just a few crumbs on it or an instant read digital thermometer reads 200°F to 205°F when inserted into the middle of the loaf. Let cool.
Once the bread has cooled completely, make a thick glaze by whisking the powdered sugar, lemon juice, milk, and butter in a medium bowl. Adjust as needed by adding more lemon juice or more powdered sugar until the glaze is pourable but not too thin. Drizzle over the loaf, then let set up for at least 30 minutes before slicing and serving.
1 1/2 cups (180g) powdered sugar, 1 Tablespoons lemon juice, 1 Tablespoon milk or heavy cream, 1 Tablespoon salted butter