This dense cheesecake is likely to crack; to keep cracking to a minimum, avoid overbeating.
Heat oven to 325 degree F. For crust, combine the ground walnuts, crushed zwieback, and melted butter. Press mixture onto the bottom of an 8-inch springform pan.
For filling, beat together ricotta cheese, eggs, and milk in a medium mixing bowl with an electric mixer on low to medium speed just until combined. Add blue cheese, basil, and rosemary, beating at low speed just until nearly smooth.
Place springform pan in a shallow pan to catch any drips. Pour filling into pan. Bake about 40 minutes or until center appears nearly set when gently shaken.
Cool for 15 minutes in pan on a wire rack. Loosen the crust from the sides of pan; cool 30 minutes more. Remove sides of pan. Cover and refrigerate at least 3 hours or overnight.
To serve, cut into wedges. If desired, garnish with fresh rosemary. Makes 20 servings.
Wrap cooled cheesecake in freezer wrap. Label and freeze up to 1 month. Thaw overnight in refrigerator before serving.