Over medium heat, add the olive oil and butter. Once the butter melts, introduce the onions and stir every few minutes. Caramelizing onions takes about 45–60 minutes. If they start drying out, add a splash of water and stir. Bring a medium pot of salted water to boil after about 40 minutes.

Once the onions are beautifully caramelized, stir in the thyme and minced garlic. Cook for about two minutes until fragrant.

Stir in the white grape juice and let it cook until it reduces by half, about three to four minutes.

Sprinkle in the flour and allow it to cook for one to two minutes until slightly thickened. Mix in the dijon mustard and worcestershire sauce until well blended.

Pour in the beef stock along with a bay leaf. Bring to a boil before lowering to simmer for about six or seven minutes until it reduces slightly. Season with kosher salt and freshly cracked black pepper as needed.

Drop the gnocchi into boiling salted water. Once they float, they are done. Drain and transfer them into your sauce mixture. Stir gently to coat.

Top the gnocchi mix with freshly grated parmesan cheese followed by gruyère cheese. Broil for three to five minutes until the cheese melts.

Garnish with fresh thyme sprigs if desired before serving immediately with crusty bread or salad.