Preheat an oven to 350 degrees F (175 degrees C). Grease 2 loaf pans; sprinkle sugar into the bottom and on the sides of the greased pans.
Beat the eggs, 2 cups sugar, vegetable oil, vanilla extract, lemon extract, and lemon zest together in a large bowl.
Mix the flour, salt, baking soda, and baking powder together in a separate bowl; add to the egg mixture and stir until the batter is thick. Fold the zucchini into the batter. Pour the batter into the prepared loaf pans.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.