Preheat your oven to 350°F or 175°C. Line a loaf pan with parchment paper or grease lightly with butter. Proper preparation helps the bread release easily after baking while keeping the beautiful loaf shape intact and neat.

In a medium bowl, whisk together flour, baking powder, baking soda and salt carefully. Mixing dry ingredients separately helps distribute the leavening evenly throughout the batter. This step creates soft texture and even rise while baking inside the oven.

In a large bowl, whisk sugar, eggs, vegetable oil, sour cream, lemon juice, lemon zest and vanilla extract together. The mixture should look smooth and creamy. Fresh lemon adds bright flavor while sour cream helps keep the bread moist and tender.

Gradually add the dry ingredients into the wet mixture while stirring gently with a spatula. Mix only until combined because overmixing can create dense bread. The batter should look thick, soft and slightly creamy before adding the rhubarb pieces.

Add chopped rhubarb into the batter and fold gently until evenly distributed. The rhubarb brings tart fruity flavor and beautiful texture. Fresh rhubarb softens while baking and creates little juicy pockets throughout the soft lemon bread.

Transfer the prepared batter into the loaf pan carefully. Spread the top evenly using a spatula. Even batter placement helps the bread bake properly and creates smooth golden appearance once fully baked and cooled later.

Place the loaf pan into the preheated oven and bake for about 50 to 55 minutes. The top should become golden brown while the center feels set. Insert a toothpick into the middle to check if the bread is fully baked.

Remove the bread from the oven carefully and let it cool inside the pan for 10 minutes. Transfer onto a cooling rack afterward. Cooling first helps the lemon glaze stay beautifully on top instead of melting completely into the bread.

Whisk powdered sugar and lemon juice together until smooth. Drizzle the glaze generously over the cooled bread. The sweet lemon topping adds bright citrus flavor while making the loaf look bakery-style, fresh, and extra delicious for serving.