Preheat the oven to 400°F.

Heat a large non-stick skillet over medium heat with a little oil. Sear the chicken for about 5-6 minutes per side, until cooked through. Remove, let rest, then chop into bite-sized pieces.

In a separate large pot or dutch oven, heat 2 teaspoons of oil over medium-low heat. Add the bacon pieces and cook until the fat has rendered and the edges are slightly crispy. Remove and set aside.

Add the onion, carrots, and celery and cook for about 3-4 minutes over medium heat, until they begin to soften. Add the garlic and mushrooms and cook for another 3-4 minutes, until the mushrooms have released their moisture and started to brown.

Sprinkle the flour over the vegetables and mushrooms and stir well to coat everything.

Gradually pour in the chicken stock while stirring constantly to prevent lumps. Add the heavy cream, thyme, rosemary, salt, pepper, and chicken bouillon. Simmer for about 3–5 minutes, stirring occasionally, until the sauce thickens.

Divide the filling between 4 oven-safe ramekins. Cut puff pastry into pieces slightly larger than the ramekins and place one over each. Gently press the edges down around the ramekins and cut a small slit in the center of each pastry.

Brush the puff pastry with beaten egg. Place the ramekins on a baking sheet and bake at 400°F for about 6-10 minutes, or until the pastry is puffed and beautifully golden brown.

Let them cool for a few minutes before serving - the filling will be very hot!