Streusel Topping
1/3 cup brown sugar
1/2 teaspoon ground cinnamon
1 tablespoon unsalted butter
1/2 cup finely chopped walnuts (I ground mine in my little mini prep)
Muffins
2 1/2 cups all purpose flour
1 teaspoon baking soda
2 teaspoons baking powder
1/2 teaspoon ground cinnamon
1/8 teaspoon salt
1 1/3 cups light brown sugar
2/3 cup vegetable oil
1 tablespoon grated orange zest (you could really sub the citrus of your choice)
1 egg
1 cup buttermilk
2 teaspoons vanilla extract
about 2 cups diced strawberries