TV chef, Simon Rimmer says: "Mushrooms should be fried in a very hot pan to seal in moisture and create a lovely crispy texture. Make sure your pan is almost smoking hot before adding the mushrooms to it.
"To ensure you’re getting a really good temperature for frying mushrooms, it’s essential to have the right kind of pan. A good quality, heavy-based pan is best for conducting heat and keeping your pan hotter for longer."
- Make sure the mushrooms are clean by gently brushing any dirt off with a clean, damp cloth or soft brush. Chop the mushrooms into quarters
- Using a non-stick frying pan, heat the butter and sunflower oil over a high heat. Make sure the pan is almost smoking hot before adding in the mushrooms.
- Cook for around 3 minutes before adding in the crushed garlic and - slightly reducing the temperature - continue cooking for a further 2 minutes. Stir in the crème fraiche, tarragon and season to taste with salt and pepper.
- While the mushrooms are cooking, toast the brioche on both sides under a hot grill. If serving with pancetta heat a second non-stick pan and crisp the pancetta using a splash of sunflower oil.
- To finish, top each slice of brioche with some of the watercress and half of the mushrooms. If using pancetta, sprinkle each with the pancetta.