Step 1

Preheat oven to 350 degrees with the baking rack in the middle. For a rectangular cake: Line 2 large 12" x 18" or 15" x 21" baking sheet pans lined with parchment or silicone mats & set aside (alternatively butter and flour the sheet pans). For a round cake - butter and flour three 8-inch round cake pans*

Step 2

Mixture 1: In a bowl of a stand mixer whip together 4 eggs, 1 cup sugar, and ½ tsp salt for ~10 minutes. Eggs should be whipped until the mixture flows off the beater in a ribbon that takes 2-3 seconds to disappear.

Step 3

Mixture 2: When the eggs are almost done whipping, in a medium bowl whisk together 1 cup sour cream, 1 can dulce de leche and 1 tsp of baking soda until no lumps of dulce de leche are seen. The mixture will increase in volume from the baking soda, so make sure to use big enough bowl.

Step 4

Combine: Fold the two mixtures together, being careful not to overmix and deflate the batter.

Step 5

Add the dry: Sift in 2 cups of flour and 2 teaspoons of baking powder, then fold the batter until fully incorporated. Do not overmix or the cake will be tough.

Step 6

Pour & Bake: Divide the batter between the 2 prepared baking sheet pans (or 3 rounds ones for a round cake) into an even layer. Bake for ~9 minutes for the rectangular pans or ~12 min for round cake pans, or until the top is lightly golden and springs back when touched, or when the toothpick inserted into the middle comes out clean. Remove from the oven, allow to cool for 5 minutes, then invert onto a cooling rack to cool completely.

Step 7

Roast: Preheat oven to 325F° with the baking rack in the center.Place the hazelnuts onto a rimmed baking sheet and bake for about 15 minutes, tossing the nuts about every 4 minutes and tasting to see if they're roasted to your liking. Remove from the oven and allow to cool completely.

Step 8

Skin the hazelnuts: Add the nuts to a ziplock bag and keep shaking and rubbing the hazelnuts between the palms of your hands until the skin is removed. Next, shake the bag so that hazelnut skins sink to the bottom of the bag, and remove the nuts to a separate bowl, discarding the skins. Leave 20 or so hazelnuts whole, chop the rest of the nuts with a sharp knife to a medium size, or pulse a few times in the food processor, or add to a ziplock bag and crush with a rolling pin.

Step 9

Combine the evaporated milk and the dulce de leche with a whisk or an immersion blender until smooth. Pour into a squirt bottle if available.

Step 10

If using heavy whipping cream instead of whipped topping, whip the cream with a mixer until medium peaks and refrigerate.

Step 11

Whip 8 oz of cubed room temperature butter and 8 oz cubed cream cheese for about 4-5 minutes or until the mixture is very fluffy. Scrape down the bowl several times throughout. Add the dulce de leche in 2 additions and whip after each until just incorporated.

Step 12

Fold in the refrigerated whipped cream (or whipped topping) into the caramel cream in two additions.

Step 13

Flip each cake upside down and peel off the parchment paper or the silicone mat from the back. Cut the rectangular cakes widthwise into two equal pieces (you will have 4 cake layers now). For the round cakes use a long serrated knife to split each cake layer in half, horizontally (giving you 6 total layers).

Step 14

Reserve about 2 cups of cream and set aside (1 1/2 cups for a round cake)Place a dab of frosting onto the serving plate. Now top with the fist cake layer and press to adhere. Layer the cake by soaking each layer with the soaking syrup, then spreading some caramel cream and sprinkling some chopped hazelnuts. Repeat the process with the rest of the layers.

Step 15

Add the final layer, then use 1 1/2 cups of the reserved caramel cream (1 1/4 cups for round) to cover the top and sides of the cake.

Step 16

Cover the cream with chocolate flakes by sprinkling the top and pressing it against the sides. OR prepare chocolate ganache and pour it over the top of the cake.

Step 17

Use the remaining cream ( 1/2 cup for rectangular or 1/4 cup for round) to pipe on cake top and decorate with whole roasted hazelnuts (use chopped hazelnuts for round version).

Step 18

Refrigerate the cake for about 2-3 hours before serving. Serve cold or room temperature.