Preheat the oven to 375 degrees Fahrenheit. Lightly grease two 9x5 inch loaf pans. In a medium sized bowl add the flour, baking powder and salt and set aside. In another medium size bowl mix together the sugar and vegetable oil. Add the egg, milk, vanilla, and mix until smooth and creamy. Add to the dry ingredients and mix until incorporated.
Add the blueberry fruit filling to the batter and gently fold in with a wooden spoon. Be careful not to over mix, the blueberry filling should be swirled throughout. Split the batter and pour it into the prepared loaf pans.
To make the streusel topping:
Combine cubed cold butter, flour, and brown sugar and use a pastry blender or fork to form crumbs. Top the bread with the crumb topping.
Bake for 50-60 minutes or until toothpick inserted in center comes out clean. (If the top starts to brown to fast, tent the bread with foil.) Remove bread from the oven and let cool for about 15 minutes. Remove the bread from the pans and let cool completely on a wire rack.
To make the lemon glaze:
Whisk together the powdered sugar, heavy cream, and lemon juice. Drizzle on top of bread.