Hot Caramelized Onion Dip

1 Preheat the oven to 425℉. Spray a small casserole dish with nonstick baking spray, and set aside.
2 Melt [wprm-ingredient text="¼ cup unsalted butter" uid="1"] in a large saucepan over medium heat. Add [wprm-ingredient text="1 tablespoon olive oil" uid="2"].
3 When the butter and oil are hot, add [wprm-ingredient text="2 large yellow onions" uid="3"] that are thinly sliced. Season with [wprm-ingredient text="1 teaspoon kosher salt" uid="4"].
4 Cook for 20-30 minutes, stirring constantly, until dark brown and caramelized. You will have around [adjustable]1 ½ cups (~265 grams)[/adjustable] caramelized onions at this point.
5 Remove the skillet from the heat. Pour in [wprm-ingredient text="1 teaspoon Worcestershire sauce" uid="5"], and stir until it’s evaporated. Season with the fresh thyme leaves, too.
6 Add [wprm-ingredient text="8 oz. cream cheese" uid="6"] and [wprm-ingredient text="½ cup sour cream" uid="7"]. Stir until combined.
7 Add [wprm-ingredient text="¾ cup shredded gruyere cheese" uid="8"]. Stir to combine. Sprinkle in the [wprm-ingredient text="1 tablespoon fresh thyme leaves" uid="9"], and stir to combine.
8 Transfer the dip to the prepared casserole dish. Sprinkle with the remaining [wprm-ingredient text="⅓ cup shredded gruyere cheese" uid="10"].
9 Bake in the preheated oven for 12-15 minutes, or until the top is dark brown and bubbly.
10 Garnish with additional fresh thyme leaves. Serve immediately with your favorite dippers.