Crush the ETİ Kakaolu cookies in a mixer. Melt the butter without burning it. Lightly grease a 20 cm springform cheesecake pan. Dump the cookies into the melted butter and mix well. Set aside one tablespoon of the mixture for decorating the top. Spread the remaining mixture into the bottom of the greased cheesecake pan and press down with your hand. Refrigerate for 15 minutes. Make 3 small balls from the mixture you set aside and refrigerate them. Melt the gelatin without boiling it. Grate the peel of one orange. Add the sugar, two egg yolks, cheese, gelatin and orange juice and mix with a mixer. Pour the mixture on top of the hardened cookies and cover with aluminum foil. Refrigerate for 1.5 hours. Fillet the orange into slices with a sharp knife, removing the white membranes. Before serving the cheesecake, garnish with orange slices and cookie balls.