How to Make It
Preheat oven to 350°.
Coat a 12-cup Bundt pan with cooking spray; dust with breadcrumbs.
Place granulated sugar and butter in a large bowl; beat with a mixer at medium speed until well blended (about 2 minutes). Add eggs, 1 at a time, beating well after each addition. Add vanilla and sour cream; beat until well blended.
Lightly spoon flour into dry measuring cups, and level with a knife. Combine flour, baking powder, baking soda, and salt in a medium bowl, stirring with a whisk until well combined. Add flour mixture to sugar mixture, stirring just until combined.
Spoon half of batter into prepared Bundt pan; sprinkle evenly with hazelnuts. Drop small spoonfuls of chocolate spread over nuts. Spoon remaining batter over chocolate spread; swirl batter using the tip of a knife. Bake at 350° for 55 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack for 15 minutes; remove cake from pan. Cool completely on a wire rack. Sprinkle cake with powdered sugar.