Preheat oven to 400 degrees. Spray 12 count muffin pan with cooking oil lightly for spill-over and line with cupcake foil liners. Combine the oil, egg and cream; set aside. Mix together the flour, sugar, salt, and powder. Add the liquids to the flour mixture and mix by hand just until blended. Fold in the blueberries. Fill muffin tins to just below the top; this provides for a large muffin top. Next, mix together the topping ingredients; cutting the butter into the mixture to form crumbs. Sprinkle on top of batter. Bake until mufifn tops are set to touch about 20 to 22 minutes. Let cool and gently remove from pan.