Step 1: Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line it with parchment paper for easy removal of the lemon rhubarb loaf with glaze.
Step 2: In a medium bowl, whisk together the flour, baking powder, and salt. In a separate bowl, toss the diced rhubarb with 1 tablespoon of the flour mixture to prevent sinking.
Step 3: In a large mixing bowl, cream the butter and granulated sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla and lemon zest.
Step 4: Gradually add the dry ingredients to the wet ingredients, alternating with the sour cream. Begin and end with the flour mixture, mixing just until combined.
Step 5: Gently fold in the prepared rhubarb. Pour the batter into the loaf pan and bake for 50-60 minutes, or until a toothpick comes out clean.
Step 6: Let the loaf cool in the pan for 10 minutes before transferring to a wire rack. Whisk together powdered sugar and lemon juice, then drizzle the glaze over the warm lemon rhubarb loaf with glaze.