Heat the olive oil in a large skillet. Add the garlic and anchovies and cook over low heat until fragrant, about 2 minutes. Add the scallions and cook, stirring, until softened, about 1 minute. Add the chicken stock and boil over moderately high heat until reduced by half, about 5 minutes. Add the cream and simmer over low heat until reduced to 1 1/2 cups, about 4 minutes. Pour the cream over the cauliflower.