Use a small bowl to make your crumble topping. Use a fork to mix it together, lightly breaking the butter into the mixture, the mixture will have a coarse texture. This will be your strusel topping.
Preheat oven to 350 F.
Take a large bowl and add 1 cup of your flour, sugar, salt, and baking powder. Mix it all well. In another bowl mix the oil, vanilla, egg, and milk. Now mix it well with the flour mixture
Gently fold the remaining flour in with your blueberries to coat (to help them not sink to the bottom). Lift out to allow excess to fall off, then add to the batter and gently fold together to incorporate.
Fill muffin papers 3/4 of the way full. Add topping to the top of each one and gently touch so it stays on the top.
Bake for 18-20 minutes. Check at 18 and every few minutes after, remove when the top springs back when gently touched in the center. Or put a toothpick in the center and when it comes out clean, remove promptly.