Preheat oven to 350°F (180°C). Spray an 8½x4½-inch loaf pan with baking spray with flour. Line pan with parchment paper, letting extra prolong over sides of pan.
Within the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar at medium velocity till fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one after the other, beating effectively after every addition. Beat in vanilla.
In a medium bowl, whisk collectively flour, baking powder, and salt. With mixer on low velocity, add flour combination to butter combination in three additions alternately with bitter cream, starting and ending with flour combination, beating simply till mixed after every addition.
In one other medium bowl, stir collectively one-third of batter (about 1⅓ cups or 325 grams), melted chocolate, and cocoa till mixed.
Unfold one-third of vanilla batter (about 1⁄2 cup or 216 grams) in backside of ready pan. Spoon vanilla and chocolate batters by heaping tablespoonfuls (about 15 grams every) in a checkerboard sample into pan (3 scoops huge alongside brief aspect). Faucet pan on a kitchen towel-lined counter 2 to three occasions to assist stage batter and fill pan. Create one other layer of batters in a checkerboard sample, inserting vanilla on prime of chocolate from first layer and vice versa. Faucet pan once more. Repeat with any remaining batter. Utilizing a knife, swirl batters collectively in a zigzag sample by way of size and width of pan. Faucet pan to assist stage batter and fill in any gaps.
Bake till a picket choose inserted in heart comes out clear or an instant-read thermometer inserted in heart registers 200°F (93°C), 1 hour and 20 minutes to 1½ hours, protecting with foil to stop extra browning, if obligatory. Let cool in pan for 10 minutes. Take away from pan, and let cool utterly on a wire rack.
Wrap cooled cake in plastic wrap, and refrigerate for 1 hour.
Unwrap cake, and return to wire rack. Pour Hazelnut Crunch Ganache throughout prime and sides of cake, spreading with an offset spatula to completely cowl. Refrigerate till set, about 10 minutes, or let stand at room temperature for 25 minutes. Retailer in an hermetic container for as much as 3 days.
