01 -
Preheat the oven to 350°F (175°C). Line an 8.5x4.5-inch (21.5x11.5cm) or 9x5-inch (23x13cm) loaf pan with parchment paper.
02 -
Combine sugar and lemon zest in a large bowl, rubbing them together until the sugar is fragrant and coated with lemon oils.
03 -
Add eggs to the sugar mixture and whisk until smooth. Add melted butter, sunflower oil, vanilla extract, and sour cream; whisk until well combined.
04 -
Sift the flour, baking powder, baking soda, and salt into a medium bowl.
05 -
Gently fold the dry ingredients into the wet ingredients. Add milk and continue folding until combined without over-mixing. Ensure no pockets of flour remain.
06 -
Spoon the batter into the prepared loaf pan, spreading it evenly. Use a spatula to create a center split down the length of the batter for an even rise.
07 -
Bake for 45-55 minutes until a skewer inserted in the center comes out clean. Cool in the pan on a rack for 10 minutes, then transfer the loaf to the rack to cool completely.
08 -
In a medium bowl, whisk powdered sugar, lemon juice, milk, and a pinch of salt until smooth. The icing should be thick yet flowy. Avoid adding excess liquid to maintain consistency.
09 -
Pour the icing over the cooled loaf, allowing it to drip slightly over the edges. Let the icing set until firm before slicing and serving.