Preheat the oven to 165 C. Prepare two loaf pans by buttering and flouring them, or by lining them with baking paper.
Mix together the melted butter, yogurt, eggs, and lemon zest.
Add the flour, sugar, baking soda, and salt and gently fold together until you have a smooth batter.
Divide the batter evenly between the two prepared loaf pans.
Bake the loafs for 40 - 50 minutes. A knife inserted into the center should come out clean when done. Let cool on a wire rack before removing them from the pan to glaze.