• 2 Tbsp olive oil
• 2 Tbsp unsalted butter
• 2 onions - minced (~2 cups)
• 4 med garlic cloves minced (~4 tsp)
• 2 Tbsp chopped fresh thyme leaves or 2 tsp dried
• 2 1/2 tsp salt
• 1/2 tsp ground black pepper
• 5 lb russet potatoes (about 10 med) peeled and sliced into 1/8“ thick with food processor
• 1-15oz. low-sodium chicken broth
• 1 5/8 cup half and half
• 1 Tbsp corn starch
• 4 bay leaves
• 7 oz cheddar cheese shredded

1. Heat oven to 400 deg with oven rack in middle position
2. Melt oil and butter in 8 qut stock pot until foaming subsides. Add onions and cook, stirring occasionally, until soft and lightly browned, about 4 min. Add garlic, thyme, salt, and pepper; cook until fragrant, about 30 sec. Add potatoes, chicken broth, cream, corn starch blended in milk and bay leaves and bring to simmer.
3. Simmer covered until potatoes are almost tender(paring knife in and out with some resistance), about 10 min. Discard bay leaves.
4. Transfer mixture to 13×9 stainless baking pan and bake for 10 min.
5. Remove pan from oven and sprinkle evenly with cheese. Bake for an additional 15 min. until bubbling around edges and top is golden brown.
6. Cool 15 min before serving.
7. Half size batch reduce quantity by 2 and bake in 8×8 baking dish.

Total time: 1 hour; 20 min pot; 25 min oven, 15 min rest
Source: Cook's Illustrated March/April 2003