In a food processor grind gingersnaps, sugar, pecans running slowly. Add softened butter. Press into bottom of a nine inch springform pan. Freeze 15 minutes or make 2-3 days before.
Preheat oven to 350. Blend all ingredients well. Pour into pan, and bake 45 minutes. Center will not be firm. You may use a water bath in the cooking process if you wish.
Beat cream, adding sugar and liqueur until stiff peaks form. Cover sides and top of cooled cheese cake. Sprinkle with toasted nuts, and refrigerate 12 hours or overnight. Let stand 30 minutes before serving.