Muffins:
2 cups flour
3/4 cup sugar
2 teaspoons baking powder
1/2 cup butter, melted
2/3 cup buttermilk
2 eggs
1 teaspoon vanilla extract
1/4 cup vegetable oil
1-1/2 cups fresh cranberries
Topping:
1/4 cup sugar
3 tablespoons flour
1 tablespoon butter, melted
1 teaspoon cinnamon
Preheat oven to 375 degrees F. Place all muffin ingredients except cranberries in a food processor bowl fitted with a steel blade. Pulse 5 times, add the berries, and process until just mixed.
Fill greased or paper-lined muffin tins two-thirds full or less and sprinkle with topping. Bake 15 minutes for miniature muffins, 25 for regular-size muffins.