Heat the oven to 350 degrees. Place a piece of wax paper at the bottom of a loaf pan that measures 5 x 9 inches. (Using a pencil, outline the bottom of the pan on a sheet of waxed paper and then cut it out with scissors.) Spray the pan and waxed paper with cooking spray that prevents sticking. Put aside.
In a bowl, mix together the flour, pudding mix, baking powder, baking soda, and salt. Use a mixer to mix together the eggs, sugar, butter, vanilla, lemon flavor, lemon juice, oil, and yogurt. Mix until everything is well mixed. Slowly mix the powdery ingredients into the liquid ones, pausing to scrape the sides of the bowl. Put the grated lemon peel in and stir until everything is mixed together. Put the mixture into the loaf pan that has been prepared. Bake for 55 minutes, or until the middle is completely cooked, and a toothpick comes out clean when inserted.
After baking, let it cool in the pan for 5 to 10 minutes. Use a knife to go around the edges of the pan, flip it over, and take the cake out, making sure to remove the wax paper from the bottom. Let it cool completely on a rack.
To make the frosting, mix the butter, lemon juice, and lemon extract using a hand mixer or a stand mixer. Slowly mix in the powdered sugar until the mixture is smooth and creamy. Spread the frosting evenly on top of the bread. Put the cake in the fridge until the frosting hardens completely before cutting. Put any extra food in a sealed container in the refrigerator.