First Step: Preheat your oven to 350°F (175°C). Grease a 9×5 inch loaf pan with cooking spray or butter. For easier removal, line the pan with parchment paper, leaving an overhang on the sides. This preparation ensures the bread does not stick and bakes evenly. Proper preparation of your pan prevents a messy cleanup and ensures your bread releases cleanly in one piece.

Second Step: In a large bowl, whisk together the flour, baking soda, baking powder, and salt. For gluten-free options, use the appropriate flour blend here. Sifting the dry ingredients helps to aerate the flour and ensure even mixing. This simple step can make a significant difference in the final texture of your bread, preventing lumps and incorporating air for a lighter crumb.

Third Step: In a separate large bowl, beat the softened butter with granulated and brown sugars until creamy and light. This process, called creaming, incorporates air into the butter, contributing to the bread’s fluffy texture. Add the eggs one at a time, mixing well after each addition. Then add the sour cream and vanilla extract, mixing until combined. Using room temperature ingredients helps them blend together smoothly for a uniform batter.

Fourth Step: Gradually add the dry ingredients to the wet mixture, alternating with the milk. Stir gently until just combined, being careful not to overmix as this can make the bread dense. Overmixing develops gluten, which creates a tougher texture. The key is to mix only until no dry streaks remain, even if the batter appears slightly lumpy. Those small lumps will resolve during baking.

Fifth Step: Gently fold in the fresh blueberries. For best results, toss the blueberries in a small amount of flour before adding them to the batter to help prevent them from sinking to the bottom. This technique works because the flour coating helps the berries grip the batter rather than falling through it. Fold just until the berries are distributed evenly throughout the batter.

Sixth Step: Pour the batter into your prepared loaf pan, smoothing the top evenly. If using, swirl in the blueberry jam by dropping spoonfuls over the batter and running a knife through it gently. Then sprinkle the crumble topping on top. These additions create visual interest and additional flavor layers that make each slice special.

Seventh Step: Bake for 60-65 minutes. After 30 minutes of baking, cover the loaf with aluminum foil to prevent over-browning. The foil reflects heat, allowing the bread to continue cooking without developing a dark crust. Adjust baking time slightly for gluten-free or denser flour alternatives. Every oven is different, so start checking for doneness about 5 minutes before the recommended time.

Final Step: Test for doneness by inserting a toothpick into the center of the bread. If it comes out clean or with just a few moist crumbs, your bread is ready. Let the bread cool in the pan for 10 minutes before transferring it to a wire rack to cool completely before slicing. Cooling allows the structure to set, preventing the bread from crumbling when cut. This patience is rewarded with clean, beautiful slices.