Put 4 serving plates in the refrigerator to chill.
In a large bowl, whisk the apple juice concentrate, lemon juice, sour cream and salt. Add the apples, fennel, raisins, walnuts, mint and Roquefort and toss gently just until combined. Divide on serving plates. Just before serving, toast the bread and cut each slice diagonally into quarters. Arrange around the salads and serve immediately.
Courtesy Gale Gand, "Butter Sugar Flour Eggs" by Gale Gand, Rick Tramonto, Julia Moskin, Clarkson N. Potter Publishers, 1999