Preheat the oven to 350 degrees. Spray a nine inch springform pan with baking spray.
In a bowl, sift together the flour, baking powder, baking soda, and salt. Set aside.
In the bowl of an electric mixer ( or your could mix this up by hand), beat together the sugar and eggs until they're foamy.
Beat in the ricotta, butter, and vanilla. Beat until well combined. Then, add the flour mixture, stirring just until no streaks of flour appear. Stir in the hazelnuts.
Pour the batter evenly into the pan. Plop 6 dollops of the chocolate hazelnut spread all over the top of the cake. Using a skewer, swirl in the chocolate hazelnut spread.
Bake for 30 minutes, or until a toothpick comes out clean. Remove the sides of the pan and cool on a wire rack for 10 minutes. Then, using a spatula, carefully remove the bottom of the pan. Let cool completely on the rack.
Serve the cake with whipped cream or gelato.