Chocolate Marble Cheesecake

Heat oven to 350°. Toast almonds on a small baking sheet for 10 minutes, stirring occasionally. Remove from oven; reduce heat to 325°. Coat an 8-inch springform pan with cooking spray. Wrap outside of pan in foil to prevent seepage. Process chocolate wafers and almonds in a food processor until fine crumbs. Sprinkle 2 to 3 tablespoon crumbs onto bottom of pan (just enough to coat bottom lightly). Shake pan to distribute evenly. Reserve remaining crumbs.
Purée ricotta in a food processor until smooth, about 1 minute. Add cream cheese, sugar, sour cream, egg, egg whites, almond extract, flour and salt; puree until smooth. Whisk amaretto, if desired (or same amount of hot water), 2 tablespoon hot water, cocoa powder and espresso powder in a bowl until well combined. Stir in chocolate chips. Stir 1 cup plain filling into chocolate mixture. Set aside. Pour remaining plain filling into prepared pan. Drizzle chocolate filling in a circular pattern over plain filling. Using a knife, make circular strokes to create swirls in the plain filling. Add 1 inch hot water to a shallow baking pan; place springform pan in baking pan. Bake until cheesecake is firm around the edge and slightly soft in the center, 45 to 55 minutes. Run a knife around inside of pan. Remove foil; let cool on a rack. Chill 6 hours or overnight before removing sides of pan. Press reserved crumbs onto side of cheesecake.