Crusty bread for servingtoasted or not as you like
Preheat the oven to 400°F. On a rimmed baking sheet toss the cauliflower with 1 tablespoon of the olive oil, season with salt and pepper, and roast for 20 to 25 minutes until tender and lightly browned. Cool slightly.
Place the white beans, remaining 3 tablespoons olive oil, tahini, lemon juice, garlic, and salt and pepper in a food processor, and pulse well to blend. Add the hot water and the cauliflower and pulse again. You can puree it, with the motor on, or leave it chunky, as you like. Add more water or olive oil of you want to make the spread thinner (especially if you want to use it as a dip).
Sauté up some shredded Brussels spouts. Scoop a generous portion of the white bean cauliflower dip on a serving plate, and with the back of the spoon spread it out. Heap on the Brussels sprouts. Heap them. Taste, adjust seasoning, pout out some crusty bread and just scoop up the layers of autumn deliciousness.