Step 1

Preheat the oven to 350ºF. Line the bottom a 9-inch springform pan with aluminum foil and spray the foil lightly with nonstick spray. Line the sides of the pan with parchment paper.

Step 2

Add the Nutella and butter to a medium saucepan. Warm over medium-low heat, stirring constantly until Nutella is melty and smooth. Whisk in the sugar. Set aside to cool slightly.

Step 3

Once cooled, whisk in the eggs and vanilla until combined. Sift the flour, cocoa powder, and salt into the Nutella mixture and fold together with a rubber spatula just until combined.

Step 4

Spread the batter evenly into the bottom of the prepared pan. Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out with only a few moist crumbs. Leave the brownie in the pan and set it wire rack to cool completely. Or pop it in the refrigerator for 15-20 minutes.

Step 5

In a small bowl, sprinkle the gelatin over water, let stand for 5 minutes.

Step 6

Bring the Nutella and 1/2 cup of the cream to a simmer in a small saucepan over medium-high heat, whisking until the Nutella has fully melted. Remove from heat.

Step 7

Add the salt and softened gelatin; whisk until gelatin is fully dissolved. Transfer to a large bowl and cool to room temperature, stirring occasionally. The mixture will thicken slightly.

Step 8

In the bowl of a stand mixer fitted with the whisk attachment, whip the remaining 1 cup cream at medium speed until it begins to thicken, about 30 seconds. Increase the speed to high and whip until soft peaks form, about 30 to 60 seconds.

Step 9

Use a whisk to mix in 1/3 of the whipped cream into the Nutella mixture. Use a rubber spatula to fold in the remaining whipped cream until no streaks appear.

Step 10

Spoon the mousse into the pan over the brownie layer. Smooth the top with an offset spatula. Place the cake in the refrigerator and chill until set, about 2 hours.

Step 11

Warm the Nutella and cream in a small saucepan over medium-low heat, whisking until the Nutella has fully melted. Set aside to cool for 10 minutes, stir it occasionally.

Step 12

Pour the glaze over the top of the mousse layer and use an offset spatula to smooth it over. Refrigerate for at least 1 hour or until the glaze has set.

Step 13

Carefully remove the sides of the pan and dispose of the parchment paper. Serve the cake with whipped cream or fresh berries.