Preheat the grilled to medium-high. Toss the cauliflower florets in the olive oil, salt, and pepper in a large mixing bowl. Transfer to a nonstick mesh grill mat. Cover the grill and cook for 15 to 18 minutes, turning occasionally, until tender and crispy. Adjust the heat as needed to get your desired texture.
While the cauliflower is cooking, separate the leaves of the butter lettuce. Prepare the blue cheese, red onion, and other toppings.
Remove the cauliflower from the grill, transfer to the mixing bowl, and toss in the buffalo sauce. Fill the lettuce cups with as much buffalo cauliflower as desired. Feel free to cut the florets into smaller pieces if you want. Sprinkle on the toppings, and enjoy!
If you can't find or don't have buffalo sauce, combine 2 tablespoon butter, ¼ cup regular hot sauce (Frank's Red Hot works great), and ¼ teaspoon garlic powder in a small saucepan. Heat until melted.
Other topping ideas include diced celery, tomatoes, and ranch.
If you don't have a grill mat, separate the cauliflower into large florets to prevent them from slipping through the cracks.
You can also make the cauliflower in the oven. Preheat the oven to 400 degrees F, spread the cauliflower florets onto a lined baking sheet, and bake for 30 to 35 minutes until tender. Toss them in the buffalo sauce after roasting.