Step 1

Melt butter with oil in a large Dutch oven over medium heat. Add onions and sugar. Cook, stirring often, 45 to 50 minutes or until onions are caramel colored.

Step 2

Sprinkle onions with flour, and stir to coat. Add chicken broth. Bring to a boil over medium heat, and cook 20 minutes. Add hash browns and 2 cups water. Reduce heat to low, add thyme and next 3 ingredients, and simmer 30 minutes.

Step 3

Stir in cheese and half-and-half; cook, stirring constantly, over medium heat 5 minutes or until cheese is melted. Remove bay leaf before serving. Garnish, if desired.