Preheat the oven to 350 degrees F. Prepare a loaf pan with cooking spray.
Use a stand mixer with a paddle attachment or a large bowl with a handheld mixer. In the bowl, add butter and sugar, and beat until creamy - about 2-3 minutes.
Scrape down the sides, and in the eggs and vanilla. Mix until combined.
Next, add the flour, baking powder, and salt. Mix on low until it's completely incorporated, but just combined.
Finally, add the milk and lemon juice. Mix until just combined. It is a thick batter, and you don't want to overmix it.
Pour batter into the prepared loaf pan and place the pan in the oven. (For muffins, separate equally into 12 muffins in a prepared muffin tin with liners)
Bake for 45-50 minutes, until a toothpick comes out clean. (If you are making 12 muffins, bake for 20-25 minutes instead)
Let cool slightly, and make the glaze.
To make the glaze, slowly add milk to the powdered sugar until you've reached your desired consistency.
When the bread has cooled down a bit, carefully remove it from the pan, and flip it out onto a wire rack. Pour the glaze over the top (if you want some), and let cool completely.
Enjoy!