Preheat the oven to 350°F. Grease and flour a 9×5-inch loaf pan.
Dust the blueberries with 1 tablespoon flour. Set aside.
In a large mixing bowl combine the flour, baking powder, and salt.
In the bowl of an electric mixer or by hand with a whisk, beat the egg until light and fluffy. (This is the only step you can use an electric mixer. Over mixing this batter will make it tough.)
Add the oil, sugar, lemon zest, lemon juice, and lemon extract to the egg and whisk to combine.
Next, slowly add the dry ingredients to the egg mixture, alternating with the milk. Stir gently.
Fold in the blueberries.
Pour batter into the prepared loaf pan.
Mix the streusel ingredients together with a fork. It will be crumbly. Sprinkle the crumbs over the bread.
Place in the preheated oven.
Bake for 50 to 55 minutes. The bread will be done when a toothpick inserted in the center comes out clean or with dry crumbs.