Grease muffin tins thoroughly.Blend milk, oil and eggs together until well mixed. Add flour, salt and chives and blend until there are no lumps. However, do not over-mix.Fill muffin tins three-quarters full of batter. Sprinkle the cheese on top of batter.Place in cold oven and turn on to 450°. Bake for 25 minutes until popovers are puffed and lightly browned. Reduce heat to 350° and bake for another 20 minutes until crisp and firm.