Preheat oven to 350°F. Spray two 3x6-inch loaf pans with non-stick spray. Place the pans on a baking sheet.
Stir the white distilled vinegar into the milk. Allow to sit for 5-10 minutes until thickened.
At the same time, in a medium bowl, gently whisk flour, baking powder, and salt together. Set aside.
In a separate bowl, cream the butter and sugar together until light and fluffy. Use an electric mixer or a stand mixer.
Beat in the egg, 2 tablespoons of fresh lemon juice, and zest until combined.
Alternate adding flour mixture and buttermilk and mix after each addition. Be sure to not over-mix.
Pour batter into prepared baking pans and bake for about 30 minutes. Bread is done when a toothpick inserted into the center comes out with just a few moist crumbs.
Allow bread to cool for 10 minutes in the pan. Then remove it from the pan onto a wire rack to finish cooling.
For the lemon glaze:
After the bread has cooled, whisk the powdered sugar and 1 tablespoon of heavy cream (or milk) together in a small bowl.
Drizzle the glaze over the two lemon loaves.
Notes
Storage Instructions: Store at room temperature for up to 5 days in an airtight container.
Freezing Instructions: Wrap the loaf without icing tightly in a layer of plastic wrap followed by a layer of foil. Place in a resealable, freezer-safe bag. Freeze for up to 3 months. To Thaw: Thaw overnight in the refrigerator or on the counter. Prepare glaze and drizzle on top before serving.