Cheesecake

Preheat oven to 350 F (160 C). Process cookies in a food processor to fine crumbs, or put them in a bag and crush them with a rolling pin. Measure 1-1/4 cups. Chop nuts. Mix crumbs with nuts and sugar. Add melted butter and mix well. Lightly butter a 9-in. (23-cm) springform pan. Press nut mixture in an even layer on bottom and about 1 in. (2-1/2 cm) up sides of pan. Bake 10 minutes. Let cool completely. Leave oven at 350 F (160 C). Beat cream cheese with sour cream at low speed until very smooth. Gradually beat in sugar. Beat in eggs, one by one. Beat in lemon rind. If using a vanilla bean, scrape its seed with point of a knife into cheese mixture; or stir in vanilla extract. Carefully pour filling into cooled crust and bake about 45 minutes, or until firm in center. Remove from oven and cool 15 minutes. Raise oven temperature to 390 F (200 C). Mix together sour cream, sugar and vanilla. Carefully spread topping on cake in an even layer, without letting it drop over crust. Return cake to oven and bake 7 minutes. Remove from oven and cool to room temperature. Refrigerate at least 2 hours before serving. (Can be kept 3 days in refrigerator.) Remove sides of springfrom pan just before serving. Makes 8-10 servings.