Clean and wash the Brussels sprouts. Wash the meat, dab dry. Season with salt and pepper. Heat oil in a large pan. Fry the duck breasts in it, first with the skin side for 5-6 minutes, turn and fry on the meat side for 3-4 minutes.
Remove and place in an ovenproof dish. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 15 minutes. Cook the Brussels sprouts in boiling salted water for 18-20 minutes.
In the meantime, deglaze the roasting dish with orange juice and duck stock. Stir in mustard, bring to the boil and stir in the sauce thickener. Bring to the boil again, season to taste with salt, pepper and sugar. Melt butter in a pot, roast almond flakes in it.
Drain the Brussels sprouts in a sieve and toss in the almond butter. Season with nutmeg. Remove duck breast from the oven, cut open. Put duck breast, almond sprouts and some sauce on plates.
Garnish with Cape gooseberry and star fruit. Add the rest of the sauce. Croquettes taste good with it.