Arrange the cauliflower on a non stick baking sheet.
Place in oven for about 5 minutes. You are just trying to warm it up a bit and get it opened and absorbent. If you know you are going to make this ahead of time you could place the cauliflower and sauce in a bag or container and let it marinade.
After your cauliflower has warmed up, place it in a container with a lid.
Pour the sauce over it and place the lid.
Give it a good shake to make sure all of the cauliflower is covered.
Place the cauliflower back on the pan.
Put the pan back in the oven for another 10-15min depending on how you like your cauliflower cooked.