Chop carrots and leeks into rounds, making sure to use the lighter parts of the leeks. Start heating butter and olive oil in a large sauté pan

Brown leeks, carrots, and garlic in the pan.

Add the flour to the pan to soak up remaining oil to make a rou. Stir thoroughly before adding broth or bouillon water.

Bring liquid to a boil before adding the mustard and thyme. Continue to boil until about half the liquid has boiled away, storing occasionally.

Pour cream in the mixture, adding salt and pepper to taste. If desired, add chicken. (Leftover rotisserie chicken is ideal for this)

Make sure mixture is heated throughout before turning off the stove. Served with rice or toast