Blueberry & Cream Cheese Muffins

1. Line a muffin pan with wrappers; preheat oven to 400°F. Melt butter in a medium nonstick pan over low heat. Remove from heat; whisk in the oil, yogurt, vanilla, and eggs. Sift flour and baking powder into a large bowl, stir in the sugar and salt, then make a well in the middle. 2. Pour the yogurt mixture into flour well. Lightly fold the dry ingredients into the wet using a rubber spatula until the mixture has just come together. Pour in the blueberries, working them into the batter with the bare minimum of stirring. (the mixture will still look lumpy.) 3. Spoon half the batter into the prepared baking cups. The dot about 1/2 tsp. of the cream cheese on top of the batter in each half-filled muffin cup. Add remaining batter, then another 1/2 tsp. of cream cheese on each muffin. Bake the muffins for 18 to 20 minutes, or until golden. Let cool in the pan for 10 minutes, then transfer to a rack and let cool completely.