Prepare the grill for indirect cooking at 350 to 375°F.
Remove the leaves and most of the stems from the cauliflower. Cut the florets into bite-sized pieces. Toss the cauliflower with the olive oil, salt and pepper. Spread the cauliflower into a single layer on a grill-safe baking sheet.
Place the baking sheet in the indirect cooking zone. Add the alder wood chips for smoke (learn about smoking techniques) and roast with the hood closed for about 60 minutes total, turning once, until the cauliflower is well-browned (you almost can’t over do it short of burning the cauliflower).
With about 20 minutes remaining, place the vegetable stock in a medium saucepan. Reduce over medium heat, stirring frequently, until thick. Whisk in the butter until melted and thoroughly combined. Keep warm.
Remove the cauliflower from the grill once fully-cooked and toss with the reduced vegetable stock. Serve immediately.