Preheat the oven to 425 degrees. In a medium bowl, toss the cauliflower with 2 tablespoons of the olive oil and season with salt and pepper. Spread the cauliflower on a large rimmed baking sheet and roast for about 50 minutes, stirring once or twice, until tender and browned in spots. Spread the pine nuts on a pie plate and toast for about 3 minutes, until golden.

Meanwhile, in a small, microwave-safe bowl, combine the raisins, saba, and water and microwave at high power for 3 minutes. Cover and let stand until the raisins are plump, about 30 minutes.

Strain the soaking liquid into a small saucepan and simmer until reduced to 2 tablespoons, about 3 minutes. Transfer to a bowl and let cool. Whisk in 1/4 cup of the olive oil and the shallot and season the dressing with salt and pepper. Set the raisins aside.

In a large skillet, heat the remaining 2 tablespoons of oil until smoking. Season the scallops with salt and pepper and add them to the skillet in a single layer. Cook over high heat until deeply browned on the bottom, about 3 minutes. Turn and cook the scallops until lightly browned, about 2 minutes longer.

In a bowl, gently toss the cauliflower with the pine nuts, raisins, tarragon, and dressing. Season with salt and pepper and transfer to plates. Top with the scallops and serve right away.

Saba is the sweet reduction of grape must; thick and syrupy, it's similar to aged balsamic vinegar.