Preheat the oven to 350°F (175°C). Line the bottom of a 5 x 9″ loaf pan with parchment paper, tracing and cutting to fit. Spray the pan and parchment with non-stick baking spray and set aside.
In a mixing bowl, combine the flour, pudding mix, baking powder, baking soda, and salt.
In a separate bowl, using a stand or hand mixer, combine the eggs, sugar, butter, vanilla extract, lemon extract, lemon juice, oil, and yogurt. Mix until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing well and scraping the sides as needed. Add the lemon zest and stir until just combined.
Pour the batter into the prepared loaf pan and bake for 55 minutes, or until a toothpick inserted into the center comes out clean.
Let the loaf cool in the pan for 5-10 minutes, then run a knife around the edges and carefully remove from the pan. Transfer the loaf to a wire rack to cool completely.
Frosting:
In a medium bowl, combine softened butter, lemon juice, and lemon extract. Gradually add the powdered sugar and beat until smooth and creamy.
Once the loaf is fully cooled, spread the frosting evenly over the top. Refrigerate to set the frosting before slicing.
Store any leftovers in an airtight container in the refrigerator.