Preheat oven to 350 degrees F (175 degrees C). Grease and flour one 12 cup muffin pan.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Combine the flour, baking powder, baking soda and salt; stir into the creamed mixture alternately with the yogurt. Fold in the berries.
Spoon the batter into the prepared muffin pan. Bake for 20 to 25 minutes in the preheated oven, or until a toothpick inserted into the center of a muffin comes out clean.
Cool in the pan for 10 minutes before removing to a wire rack to cool completely.
Interesting Facts
The antioxidant content in these muffins makes them a great snack for boosting your energy and immune system.
Raspberries are a great source of vitamin C, and blueberries are a great source of fiber.
These muffins make a great addition to any breakfast, snack, or dessert.