Heat the olive oil in a large skillet over medium heat. Add the cubed beef and cook until browned on all sides. Remove the beef from the skillet and set it aside.

In the same skillet, add the diced onion, carrots, and celery. Cook until the vegetables are softened, about 5 minutes. Add the minced garlic and cook for another minute.

Sprinkle the flour over the vegetables and stir to coat. Slowly pour in the beef broth, stirring constantly to avoid lumps. Add the Worcestershire sauce, thyme, rosemary, salt, and pepper. Bring the mixture to a simmer and cook until it thickens.

Return the cooked beef to the skillet and stir in the frozen peas. Cook for another 5 minutes, then remove from heat and let the filling cool slightly.

Preheat your oven to 375°F (190°C). Roll out the puff pastry and cut it into circles large enough to cover the tops of your ramekins or muffin tins. Fill each ramekin with the beef filling, then place a puff pastry circle on top. Press the edges to seal and brush with the beaten egg.

Place the ramekins on a baking sheet and bake for 20-25 minutes, or until the pastry is golden brown and puffed.