Preheat the oven to 350F.
In a large bowl, combine the flour, sugar, powdered cheese mix, baking soda and salt. Add the grated cheese and toss to combine. In another bowl, whisk together the buttermilk, melted butter or oil and egg. Add to the dry ingredients and stir with a spatula just until combined.
Divide the batter between greased or paper-lined muffin tins, filling them to heaping. (If you want larger tops that spread into each other, skip the paper liners and just spray the pan instead.)
Bake for 25-35 minutes, until golden, domed and springy to the touch. Makes about 8-10 mmmuffins.