Preheat the oven to 375°F or gas mark 5. Grease or line muffin pan.
In the food processor pulse all of the streusel ingredients together until it has the consistency of irregular small pebbles. Set aside.
In a bowl combine the flour, sugar, salt, nutmeg, cinnamon and baking powder. Mix until evenly combined and the brown sugar doesn't' have many clumps.
In another bowl mix the eggs, milk, butter, and vanilla and pour over the dry ingredients. Mix until combined and pour into the muffin pan. Bake for 20 or until a toothpick inserted into a muffin comes out clean.