To prepare the grouse
Take the grouse out of the fridge so that they can come to room temperature before you start cooking. Preheat the oven to 200°C/Gas 6. Heat a tablespoon of vegetable oil in a large heavy-bottomed roasting tin. Season the grouse very well, inside and out, then sear them in the pan until golden brown all over. Add the diced vegetables, baby onions and thyme sprigs to the pan. Place the grouse on one breast and roast in the hot oven for 3–4 minutes. Flip the birds onto the other breast and roast for another 3 minutes. Next pour brandy into both birds and place them on their back to finish roasting – another 5 minutes.
Remove the pan from the oven and leave the grouse to rest for 10 minutes breast upwards so the juices are evenly distributed. Keep all the pan juices and vegetables. Put the roasting tin back on the heat on top of the stove and begin to reduce the cooking juices. Add the chicken stock, bring to the boil and let the sauce reduce and thicken. Take off the heat and pass through a fine sieve. Keep warm until ready to serve.
To make the bread sauce
Simmer the milk with the onion stuck with cloves and cook until the onion is tender. Strain the milk into a clean pan and add the butter. Next, whisk in the bread off the heat and mix until smooth. For a smoother sauce, use a hand blender. To finish, season with salt, white pepper and nutmeg.
To make the game chips
Using the criss-cross part of a mandolin, cut the potato into slices roughly 3mm thick. Warm the oil gently on the stove. Dip a slice into the oil to check the oil is hot enough to fry. Fry the potatoes until crispy. Drain on paper towel and season lightly with salt.
To serve
Serve the rested grouse whole with pan juices, vegetables, bread sauce, game chips and some sautéed spinach and girolles.
If you don’t like bread sauce, serve with some celeriac purée