Combine the cauliflower, capsicum, onion, dill, balsamic vinegar, white wine vinegar and olive oil in a large resalable bag; shake bag to evenly coat. Allow to marinate in refrigerator 1 to 2 hours turning bag occasionally.
Preheat oven to 230 degrees C.
Open the bag and season with salt and pepper; reseal the bag and shake again to coat. Pour into a 20 x 30cm glass baking dish.
Bake in the preheated oven until tender stirring occasionally; about 30 minutes.