Heat 2 tablespoons of olive oil and 2 tablespoons of unsalted butter in a large pot over medium-low heat. Add 4 sliced onions and a pinch of salt. Cook for about 45 minutes until soft and golden brown.

Stir in 4 minced garlic cloves and cook for about 30 seconds until fragrant.

Increase heat to medium-high, pour in 1/4 cup of Irish whiskey, and scrape the pot to deglaze. Simmer for 2 minutes, then add 1.5 cups of Guinness.

Pour in 6 cups of beef stock, add 1 tablespoon of Worcestershire sauce, 3 sprigs of fresh thyme, and 1 bay leaf. Season with salt and pepper, bring to a boil, then simmer gently for 30 minutes.

Slice a baguette and toast the pieces under the broiler for about 2-3 minutes until golden and crisp.

Remove bay leaf and thyme stems from the soup. Ladle the soup into oven-safe bowls, top with toasted baguette slices, and sprinkle with 8 ounces of shredded Irish cheese.

Broil the bowls in the oven for 3-5 minutes until the cheese is melted and bubbly.

Garnish with freshly chopped parsley or chives and serve immediately with extra baguette slices.