In a large saucepan with a tight-fitting lid, bring about 1" of water to a boil.
Place the cauliflower in a steamer basket.
Arrange the peppers on top.
Set the basket in the saucepan, making sure the basket sits above the water.
Cover and steam for 10 to 15 minutes or until the cauliflower is crisp-tender.
Transfer the cauliflower and peppers to a serving bowl.
Sprinkle with the basil and gently toss until combined.