In a saucepan, melt butter over medium heat. Pour the flour and, stirring constantly with a whisk, cook a couple of minutes.
Pour in warm milk and warm cream, whisking the mixture with a whisk. Cook, stirring, for 5 minutes, until the sauce thickens.
Remove the pan from the heat, add salt, black and red pepper and grated cheese. Stir the sauce to a smooth consistency.