Evenly spread the cauliflower on a baking sheet and season with salt and pepper. Transfer to the oven and roast, tossing once with a spatula, until golden brown at the edges, about 20 minutes.
Put the butter in a small skillet over medium-low heat. Once it's melted, add the pine nuts and cook, stirring frequently, until they're lightly golden brown, about 5 minutes. Add the garlic and dates and continue cooking until they're softened, 2 to 3 minutes more; season with salt.
Transfer the hot cauliflower to a serving bowl, drizzle the pine nut mixture over the top and toss to combine. Taste and adjust seasoning if necessary and serve warm or at room temperature.