This family favorite is perfect for a weeknight. Make it ahead if you're expecting company or dropping off dinner for a friend!
Bring chicken stock to boil in a skillet with a lid. Add chicken breasts and poach for about 10 minutes.
Meanwhile, cook broccoli, drain, and layer into a 13x9 casserole dish.
Sauté shallots in butter and olive oil for a few minutes, then sprinkle in flour and whisk for about a minute.
Stir in wine and reduce for about a minute, then ladle in about half of the chicken stock. You can add more for a thinner sauce, but our family prefers it a bit thicker.
Add nutmeg, salt, and pepper.
Slice chicken in 1/2 strips and add to the pan, stirring until they're coated with sauce.
Pour the chicken over the broccoli and then top with grated Gruyere.
Broil for 3-5 minutes until the cheese is golden and bubbly.
Serve over white or brown rice.