In a large skillet over medium-heat, swirl the olive oil to coat the pan. Add the shallot and cook for 3 to 4 minutes until softened. Add the cauliflower and season with salt and pepper. Cook, tossing as needed, to brown all sides, 4 to 6 minutes. Add the apple, thyme, and water. Cover and cook until tender, 8 to 10 minutes. Stir in the butter and sprinkle with pecans.