Take out the heated tray and spray or brush with oil. Pour in the batter to almost full, divide the grated cheddar between them and slightly press down (don’t scrimp on the cheese – this will give you the popover shape). Put the tray in the oven, turn down to 180C/fan 160C/gas 4 and bake for 15 minutes. After 15 minutes, turn the tray around and bake for a further 30 minutes. Allow to cool slightly and gently twist to help ease them out of the tray. Serve with salted whipped butter or truffle butter.