Preheat oven to 400 degrees F. Line muffin tine with paper liners.
In a small bowl, stir together cream cheese, sugar, and flour until combined well. Filling keeps, covered and chilled up to one week.
In a large bowl, sift together flour, sugar, baking soda, salt, cinnamon, and nutmeg and stir in cereal. Add eggs, buttermilk, and oil, stirring just until combined well. Batter keeps, covered and chilled up to one week.
Spoon one heaping tablespoon batter into each tin and top with 2 teaspoons filling. Spoon 1 heaping tablespoon batter over filling, spreading to cover filling completely. Bake muffins in middle of oven 20-25 minutes, or until a tester comes out clean.