streusel in the middle. I normally make the sour cream coffee cake out of "Cake Bible." Ruth Birenbaum's recipe has more depth of flavor than this recipe and way less fussy in making. Surprisingly for 12 muffins I used 3 bowls and many steps. My family definitely wants them again because we ate 10 muffins in 2 days, with 2 going to my brother-in-law as a celebration of his 50th birthday.