Preheat the oven to 400F and set out four 8 oz. ramekins. Sprinkle the cubed beef with the salt and pepper.

In a large pot, heat the olive oil over high until it’s shimmering and hot. Drop the beef in and heat and allow it to brown on each side, turning with a large spoon. You don’t want it to cook completely through. Remove it from the pot with a slotted spoon and set aside.

Allow the pot to cool a bit, then add the butter and let it melt over medium heat. Add the onion and let it cook until caramelized and brown. Add the garlic and allow it to cook for a couple more minutes, or until aromatic, then stir in the flour until it coats the onions. Add the beef broth a half cup at a time, stirring/whisking well after each addition to prevent the flour from clumping. Once you have added all of the broth, allow it to continue to cook until the broth has thickened.

Stir in the beef, then taste and season with more salt and pepper if necessary. Divide the filling into the four ramekins, then top each with a thick slice of Swiss cheese.

Put a square of the puff pastry over the top, then brush the beaten egg over the top of each one. Score lightly across the top with a sharp knife, then place them on a baking sheet. Bake for 20-25 minutes, or until the tops are golden brown and it has puffed high. Remove from the oven and serve while still warm and the cheese is melted.