French Onion Potatoes au Gratin

• total time: 2 hours 13 minutes

Ingredients

French Onion Potatoes au Gratin

5 Tbsp. butter, divided

3 white onions, thinly sliced

2 tsp. worcestershire sauce

3 garlic cloves, minced

2 tsp. chopped fresh thyme, plus more for garnish

3 Tbsp. flour

4 cups whole milk

2 tsp. Dijon mustard

2 (8-oz.) block Gruyere cheese, shredded and divided

4 medium russet potatoes, peeled and very thinly sliced

Directions

In a medium saucepan over medium-low heat, melt three tablespoons of the butter. Add onions and cook, stirring frequently, until dark and caramelized about 40 minutes, deglazing with a splash of water occasionally if they are sticking to the bottom. Add worcestershire sauce and season with salt and pepper. Add remaining butter to the skillet along with garlic ant thyme and saute for another two minutes, stirring constantly. Add flour and cook for another minute then slowly whisk in milk. Bring to a boil over high heat, stirring frequently, then remove from heat and stir in half of the cheese until melted.

Preheat oven to 375F. In a greased baking dish, add a layer of potatoes and season lightly with salt and pepper. Cover with a layer of sauce then a layer of extra cheese. Repeat until you’ve used all the potatoes, sauce and cheese (it should end with a layer of cheese on top.)

Cover with aluminum foil and bake for an hour. Remove foil and bake another 30 minutes, until browned and bubbly and potatoes are fork tender. Garnish with more thyme and serve.