Heat oven to 400° F. Place the baguette slices on a baking sheet and brush both sides of the bread with 2 tablespoons oil. Bake until golden brown, 4 to 5 minutes per side.
On a rimmed baking sheet, toss the cauliflower with the remaining 2 tablespoons oil; season with ¼ teaspoon each salt and pepper. Roast until tender, 25 to 30 minutes. Add the raisins and capers and toss to combine.
Dividing evenly, spread the goat cheese on the toasted baguette slices and top with the cauliflower mixture.