Line a muffin tin with paper liners. Preheat oven to 375F.
Mix all dry ingredients together in a medium to large mixing bowl.
2 cups flour, ¾ cup sugar, ½ teaspoon salt, 1 teaspoon baking powder, 1 teaspoon baking soda
Lightly beat the eggs and add in the Greek yogurt, oil, and vanilla. Mix until well blended.
1 cup Greek yogurt, ⅔ cup canola oil, 2 eggs, 2 tablespoons vanilla extract
Add wet mixture to the dry and mix just enough to blend.
Fold in the dried cranberries, walnuts and orange zest. Do not overmix to ensure a tender muffin.
1 ½ cups dried cranberries, ½ cup walnuts, 1 tablespoon orange zest
Divide the batter among 12 muffin cups.
In a small bowl, combine streusel ingredients. Spoon on top of the muffin batter in each cup.
¼ cup oats, ¼ cup brown sugar, ¼ cup flour, ¼ cup walnuts, optional: 1 tablespoon butter, melted
Bake in the preheated oven for 30 to 35 minutes.
Cool 5 minutes in pan, then remove muffins to cool completely.