Chicken breasts are fabulous because they are fast, nutritious, and delicious, and I bet you have a few go-to recipes for chicken dinners. But let's face it: The same old recipes can get boring night after night. So let me introduce you to this classic, elegant mustard sauce -- you won't believe how simple and quick it is! Once you try it, you'll want to put it on everything, and I say go for it (it's also great on fish or steak). Serve the chicken with some steamed asparagus for a meal that looks and tastes like it came from a fancy French restaurant, but you'll know you made it at home in about 15 minutes!