In a skillet on medium heat, melt butter and add olive oil— sauté sliced onions until fragrant

Once fragrant, after 5 minutes, add garlic, thyme, Worcestershire sauce and continue to sauté on low until caramelized 

After 15 minutes, add beef stock and deglaze the pan, continue to cook until beef stock is evaporated mostly— season with salt and pepper to taste and turn off heat 

To a mixing bowl, add cream cheese, caramelized onions, parmesan cheese, half the mozzarella, half the Swiss cheese and sour cream, mix well to combine 

Transfer to a baking dish of choice and layer with mozzarella and top with Swiss cheese 

Bake 375 for 15 minutes and broil for 2 minutes  or until top is golden brown and bubbly 

Serve with toasted baguette  or chips and enjoy