Preheat the oven to 400°F (200°C). Place the puff pastry in the fridge to keep it cold until needed. Set a 9-inch pie dish or similar baking dish nearby.

Warm a large skillet over medium heat. Add the butter and olive oil. Once hot, add the onion, carrot, and celery. Cook, stirring, until softened and lightly golden, about 8–10 minutes.

Add the garlic and cook for 30 seconds until fragrant. Stir in the chopped mushrooms and a pinch of salt. Cook until the mushrooms release their moisture and it mostly evaporates, 6–8 minutes. You want a fairly dry mixture.

Increase the heat to medium-high. Add the rabbit mince, breaking it up with a spoon. Season with 1 teaspoon salt, black pepper, thyme, and rosemary if using. Cook until no longer pink and lightly browned in spots, 5–7 minutes.

Stir in the tomato paste and cook for 1 minute to caramelize slightly. Sprinkle the flour over the mixture and stir well for 1–2 minutes to coat; this helps thicken the filling later.

Pour in the white wine and let it bubble for 1–2 minutes to reduce by about half. Add the stock, Worcestershire sauce, and bay leaf. Simmer gently for 8–10 minutes, stirring occasionally, until the mixture thickens and becomes glossy.

Remove the bay leaf. Stir in the cream (if using) and parsley. Taste and adjust seasoning with more salt and pepper as needed. The filling should be savory and well-seasoned.

Transfer the hot filling to your pie dish and spread it evenly. Let it cool for 10 minutes so it doesn’t melt the pastry.

Roll the chilled puff pastry slightly if needed to fit your dish. Lay it over the filling, tucking or crimping the edges. Cut 2–3 small slits in the top for steam. Brush with beaten egg and sprinkle with seeds if you like.

Bake for 25–30 minutes, or until the pastry is puffed and deep golden. If the edges brown too fast, tent with foil for the last few minutes.

Let the pie rest for 10–15 minutes before slicing. This helps the filling set and makes cleaner slices.