Pour the batter into the prepared pan. Bake until a toothpick inserted in the center emerges clean, about 50 minutes to an hour. If the top of the loaf starts to brown towards the end of baking, put a loose tinfoil tent over the pan. Let cool in pan until warm to the touch, then turn out onto a plate, before turning right side up.
Add the lemon juice, lemon zest, and powdered sugar into a microwave-safe bowl and whisk to combine. Then, add in the butter, and microwave for 45 seconds. Whisk togther until there are no lumps. If the glaze is too thick, feel free to add more sugar. If it's too thin, you may want to add lemon juice. Place the mixture into the fridge for about 10 minutes to thicken. Pour over the cooled lemon loaf.