Sift together flour, 1/4 cup sugar, baking soda and salt into bowl. Combine egg, butter/sour milk and oil in small bowl; blend well. Add all at once to dry ingredients, stirring just enough to moisten. Combine cranberries and 1/2 cup sugar; stir into batter. Spoon batter into greased 2 1/2-inch muffin-pan cups, filling 2/3rds full. Bake in 400 degrees F. oven 20 minutes or until golden brow. Serve hot with butter and homemade jelly or jam.