Scrub, trim and halve the carrots, toss with 1 tablespoon of olive oil and a pinch of sea salt and black pepper, then roast in the smaller air-fryer drawer for 35 minutes at 200ºC, shaking halfway.
Roughly tear any larger mushrooms, leaving any smaller ones whole, toss with 1 tablespoon of olive oil, then place in the larger drawer, along with 2 unpeeled garlic cloves. Cook for 15 minutes at 200ºC, or until golden all over.
When the time’s up on the larger drawer, tip the contents onto a chopping board, squeezing the garlic from their skins, then finely chop and mix everything together.
Finely slice the parsley (stalks and all), then chop them into the mushroom mixture with the butter and a squeeze of lemon juice. Season to taste with salt and pepper, then leave to cool completely.
Use the tip of a sharp knife to slice into the thickest part of each chicken breast to create pockets. Divide and stuff in the mushroom mixture, then shape the breasts back into their original form, sealing the stuffing inside.
Unroll the pastry and slice lengthways into 4 strips. Stretching slightly to lengthen, wrap the pastry around each chicken breast, pressing lightly to secure it in place.
Beat the egg and brush it all over the pastry, then place in the large drawer and cook for 20 minutes at 200ºC, or until golden and cooked through – you may need to work in batches.
Meanwhile, place a non-stick frying pan on a medium-high heat with the mustard and white wine. Allow to bubble and reduce by half, then pour in the cream and simmer until the sauce coats the back of a spoon. Remove from the heat and season to perfection.
Divide the mustard sauce between serving plates. Slice each chicken breast into 3 and arrange on top of the sauce, finishing with a drizzle of extra virgin olive oil, if you like. Serve with the roasted carrots and a handful of watercress.
