Preheat oven to 350 degrees F. Prepare 4 (8-ounce) ramekins or a 1 1/2 -quart souffle dish by greasing with softened butter and coating with Parmesan.
Make a thick bechamel sauce base by melting 3 tablespoons butter over low-medium heat in a thick-bottomed saucepan. Just as the foam subsides, add the flour, stirring constantly with a wooden spoon or whisk to prevent lumps. Cook for 2 to 3 minutes to coat the flour and remove the starchy taste, do not allow to brown. Add the hot milk to the roux and continue to whisk until the mixture is smoothly thickened. Remove from heat. Beat in the egg yolks one at a time. Season with salt, pepper, and mustard. Stir in the cheese and incorporated evenly. Chill while preparing the egg whites.
In a separate clean bowl, beat the egg whites and cream of tartar just until they hold soft peaks. Fold 1/3 of the beaten whites into the bechamel mixture to lighten it. Then gently fold in the rest. Pour into the prepared ramekins or souffle dish and place on a cookie sheet. Bake on the middle rack for about 25 minutes. The souffle is done when it has puffed over the rim, the outside is golden and the center giggles slightly. Take care not to over bake. Serve with Dried Figs in Simple Syrup, brioche, and bitter greens.
