Combine dry ingredients. Add wet ingredients and stir just until combined. Fold raisins into muffin batter. Spoon into 12 greased muffin cups, filling about 3/4 full. Combine streusel ingredients-3 tablespons brown sugar, 3 tablespoons oatmeal) and sprinkle over muffins. Bake at 400 for 20 - 22 minutes