Preheat oven to 375 degrees F. In a bowl combine dry ingredients. In another bowl whisk together wet ingredients (keep raisins and oats aside) and then slowly incorporate them together.
Fold in the oats, nuts and raisins at the end. Combine streusel ingredients in a bowl with a fork until it is crumbly and incorporated.
Spray muffin tin or add liners to cups and fill 3/4 of the way full. Sprinkle streusel on top and gently touch so it sticks to batter and stays on. Bake for 20 minutes or until toothpick comes out clean or when touched gently in the middle they spring back.