Preheat the oven to 375 degrees F. Place the sliced quinces in an ovenproof pan. Add the orange juice, vanilla bean, fennel seed, star anise, and sugar. Bring to a boil. Cover and put in the oven. Cook until when pierced with a small knife there is no resistance, about 20 minutes. Strain liquid into another pan and reduce by one-half. Set aside reduced liquid and quinces.
Cabbage: In a medium size pan, melt 1 tablespoon butter. Add the red onions and sweat until soft. Add the cabbage and mix well. Let cook for 3 minutes, or until the cabbage has softened a bit. Deglaze with both vinegars and let reduce until dry. Add the port wine and reduce until almost all the port is gone. Add the red wine and reduce until just a little liquid remains. Season, to taste, and set aside.
Venison Sauce: Heat a heavy-duty saucepan. Add the sugar and caramelize. Deglaze with vinegar and pepper. Reduce until almost all the liquid has evaporated. Add the port and reduce by 3/4, then add the red wine and reduce by 1/2. Add the stock and reduce until thick and syrupy. The sauce should coat the back of a spoon. Add the pomegranate molasses and bring to a boil. Remove from the heat and set aside.
To finish: Preheat oven to 500 degrees F. Season venison steaks with salt and pepper. Heat a large saute pan over high heat. Add 1 tablespoon of olive oil and sear the venison on both sides. Place in the oven for 5 to 6 minutes. Remove from the oven and let rest over a wire rack.
To serve: Reheat the quinces in the reduced orange juice with 1 tablespoon butter.
Reheat the cabbage in 1/4 cup chicken stock and the remaining 3 tablespoons butter.
Reheat the sauce and whisk in 1 tablespoon of butter, add the pomegranate seeds and season, to taste.
Heat 6 large dinner plates and place a mound of cabbage in the center. Leave 3 pieces of quince on cabbage at equal distance from each other. Slice the venison into 3 pieces against the grain. Place the venison between the quinces. Nap the plate with the sauce. Sprinkle with chives and serve.