| Heat oven to 350 degrees. Lightly grease and flour an 8" springform pan. Tap out excess flour. Wrap outside of pan with heavy-duty foil, molding it tightly around pan to prevent water from seeping in. Process ricotta cheese in food processor, scraping down sides once or twice until completely smooth. In large bowl, whisk eggs, sugar, flour, vanilla and grated orange zest until blended and smooth. Combine with ricotta mixture. Pour into prepared pan and spread evenly. Sprinkle chocolate chips over top. Place pan in a large roasting pan in oven. Pour hot tap water to a depth of 1 inch into roasting pan. Bake 1 1/2 hours or until top is golden and cake pulls away slightly from sides of pan. Turn off heat and leave cheesecake to cool in oven with door slightly ajar for 45 minutes. Remove from oven, then remove foil. Cool completely on wire rack. Cover and refrigerate overnight or up to 1 week. Up to 3 hours before serving, run a long, thin knife around edge of pan to loosen cake. Remove sides of pan. Brush top of cake with half the melted preserves. Top with a layer of orange slices and brush with remaining preserves. Sprinkle top with pistachios. | 
