Preheat oven to 375 degrees. [I immediately put the pinions on a baking sheet and pop them in the oven to toast them–pine nuts are sold raw rather than roasted. Watch carefully; heat them 5 minutes, just about the time it takes the oven to come up to temperature.]
Grease the muffin tin or line with cupcake papers if you wish.
Stir the dry ingredients (cornmeal, flour, baking powder, baking soda, salt) together in a large bowl; set aside.
Place butter and sugar in a large bowl. Beat with electric mixer until creamy, about 5 minutes. Beat in the eggs, yogurt or sour cream, and vanilla just until blended.
Gently stir wet ingredients into the dry ingredients just until moistened. [Do not over-beat.] Spoon the batter into the prepared muffin tin cups (fill 2/3 full).
Half-fill one muffin cup with warm water–this keeps the muffins from being dry.
Bake for 25 minutes until lightly brown and tops bounce back when tapped with your finger and a toothpick inserted in the center comes out clean. Remove from the oven and cool 5 minutes in the pan. Run a knife around the edge of each muffin to loosen from tin, then remove muffins to a wire rack to cool completely.