To prepare a Sophie Grigsons chocolate olive oil mousse recipe, first you need to prepare the ingredients for the mousse. First, you'll need the following ingredients: 1 cup (240 ml) of heavy cream 2 tablespoons of chocolate granules 1 teaspoon of vanilla extract 1 tablespoon of milk Instructions: In the bowl of an electric mixer, beat the egg yolks on medium speed until stiff peaks form. Gradually add the sugar, beating after each addition until the mixture is light and fluffy. Fold in the vanilla and chocolate chips until combined. Pour the chocolate mixture into the graham cracker crumbs and stir to combine. Cover the mixing bowl with plastic wrap and refrigerate until firm, at least 1 hour.