Mornay Sauce

Scald milk with thyme, garlic powder, salt, pepper, and bay leaf in small heavy saucepan over medium heat; remove from heat. Discard bay leaf.

Melt butter in heavy medium saucepan over medium-high heat. When foam subsides, stir in flour; cook, stirring, 2 minutes. Do not let flour color. Gradually add hot milk to flour mixture, whisking constantly until smooth and free of lumps. Reduce heat to medium-low; simmer sauce 5 minutes, stirring occasionally. Remove from heat.

Whisk egg yolks and cream in small heatproof bowl until blended. Stir in 2 tablespoons of the hot sauce, then return egg mixture to saucepan. Heat sauce over medium-high heat to boiling, whisking constantly. Reduce heat to medium low; simmer 3 minutes, stirring constantly. Stir in cheese is until melted and smooth, about 2 minutes. Simmer 3 minutes longer; sauce should be thick enough to lightly coat a spoon. Remove from heat; taste and correct seasoning.