First, bake the spice cake according to your recipe or box directions in a 9-inch spring form. Remove the cake and place on a rack to cool. With a serrated knife or an adjustable wire cake slicer gently cut the dome off the top of the cake.
Use the same spring form to bake the cheesecake.
Combine the crumbs and sugar in a bowl; add melted butter and mix well. Press onto the bottom of your springform pan. Refrigerate while you make the cheesecake mix.
Preheat the oven to 325°F.
In a bowl of an electric mixer, beat the cream cheese on low speed until free of lumps and fluffy. One at a time, add eggs mixing on low speed after each just blended. Gradually add maple syrup and beat slowly until combined. Periodically scrape down the sides of the bowl and the beaters. Add vanilla, nutmeg, and cinnamon. The batter should be well-mixed but not overbeaten. Pour the filling over crust.
Set the cheesecake pan on a large piece of aluminum foil and fold up the sides around it. Place the cake pan in a large roasting pan. Pour boiling water into the roasting pan until the water is halfway up the sides of your pan. Bake for 45-50 minutes or until just set. It should still jiggle but it will firm up after chilling. Let cool in pan for 30 minutes.
Beat the cream cheese and butter in a large bowl until smooth. Add powdered sugar, syrup, and vanilla; beat until smooth.
Loose the cheesecake gently form the sides of the pan by running a knife around the inside rim. Unmold and transfer to a serving plate. Using a spatula spread a layer of maple icing over the surface. Top with spice cake. Spread the reminder of the icing over the top and sides of the cake.
Refrigerate overnight or at least for four hours to let the flavors mend. To serve, top the cake with chopped candied walnuts and drizzle with maple syrup.