Heat the oven to 350 F.

Remove the outer leaves from the cauliflower and cut off the bottom of the stem. Cut the hard core out of the cauliflower, but take care not to cut into the florets. Rinse the cauliflower and place it in a microwave-safe dish. Microwave on 100% power for about 7 to 9 minutes, or until the cauliflower is just tender.

Remove the cauliflower to lightly greased baking dish.

Combine the mustard, olive oil, and pepper. Brush or rub the mixture over the head of cauliflower.

Bake the cauliflower for 20 to 30 minutes, or until tender.