1. Place cookies in a heavy zip-lock plastic bag and crush with a rolling pin. Pour into a buttered 9-inch round springform pan and pour melted butter over crumbs; mix to coat, then press evenly over bottom and about 1/2 inch up sides of pan. Bake in a 300° oven until crust is slightly darker and looks a bit dry, about 10 minutes (leave oven on).
2. Meanwhile, in a bowl, with a mixer on medium speed, beat cream cheese and sugar until well blended. Beat in sour cream. Add eggs one at a time, beating to blend after each addition. Beat in flour, vanilla, peppermint extract, and salt until smooth. Pour cream cheese mixture into pan over baked crust.
3. Bake until edges are just golden and center jiggles slightly when pan is gently shaken, about 1 hour. Run a knife around edge of pan rim. Place pan on a wire rack and cool cheesecake completely in pan. Cover and chill until cold, at least 4 hours or up to 2 days. Run a knife around rim again, then release rim. If any liquid has pooled on surface of cheesecake, blot dry gently with a paper towel.
4. Decorate top of cake with crushed peppermint candy, pressing it in gently with your hands.