Prepare the foie gras tortellini: Place the mushroom duxelle into a bowl and add the chopped truffle, diced foie gras, sliced chives and mix together. Season to taste with salt and freshly ground pepper. Cut the pasta dough into 2 pieces. On a lightly floured surface roll out each piece with a rolling pin until each are ½cm thick. Set the pasta machine on the thickest setting and feed one piece of pasta through it twice. Adjust the setting one notch and feed the pasta through it twice again. Continue rolling the pasta until it is on the thinnest setting. Roll the other piece in the same way. When all the pasta has been rolled, use an 8cm plain pastry cutter and cut out 12 circles of pasta.
Make the tortellini one at a time: Spoon 5g foie gras mix into the centre of each circle of pasta. Lightly brush the edge of each circle with the egg wash. Fold the pasta over to make a semi-circle and press the edges together from one side to the other, pressing out any air from the pocket. Take the tortellini in your hand and curl the two tips around the index finger and press together. Once more, press together the edges so that they are firmly joined. Repeat with the remaining tortellini.
Blanche the tortellini in salted boiling water for 2 minutes, and refresh in iced water. Drain well.
Use a sharp boning knife to remove the legs, wings and wishbones from the squab leaving the breasts on the carcass. Use the squab legs for confit in another dish. Save the wings and wishbones for making stock. Pre-heat the oven to 200°C.
Season the cavities of the squab with a generous pinch of salt and freshly ground pepper. Stuff each with a crushed garlic clove, a sprig of thyme and lightly season the skin of the squab with salt and freshly ground pepper.
Melt 40g butter in a heavy-based pan and when foaming add the shallots. Cook until golden brown, season with salt and freshly ground pepper and drain into a sieve. In a heavy-based saucepan bring the red wine jus to the boil, reduce to a simmer and add the shallots. Cook the shallots in the red wine jus until tender. Check with the tip of a knife after 15 - 20 minutes.
In a heavy-based pan heat 20ml olive oil over a medium heat. Add the squab skin side down and seal for 3 - 4 minutes until the skin is evenly brown. Stand the squab upright in the pan to ensure even cooking of the breasts and transfer to the oven to cook for a further 3 minutes or until medium rare. Remove the pan from the oven, add 20g butter and as it melts baste the breasts with it. Remove the squab from the pan and place onto a wire rack, laying them breast side down. Spoon the pan juices into the cavity. Allow the squab to rest for at least 10 minutes before boning each breast from the carcass. Save the squab carcasses as they can be chopped up and roasted further to make a sauce.
Use the pan in which the squab were cooked and sauté the lardons until brown. Remove from the pan and drain well. Heat the remaining olive oil in a heavy-based pan, add the mushrooms and sauté for 3 - 4 minutes, season to taste with salt and freshly ground pepper and drain well. Reheat the tortellini in salted boiling water for 3- 4 minutes. Drain well and lightly season with salt and freshly ground pepper. Remove the braised shallots from the red wine jus and pass the sauce through a fine chinois.
Place 2 squab breasts side by side in the centre of a warm plate. Arrange 3 tortellini