Make the chocolate peanut butter mousse--------------------.
Lightly grease the bottom and sides of a 9 1/4-by-5 1/4-by-2 3/4-inch metal loaf pan.
Line the pan with plastic wrap so that the plastic extends about 2 inches beyond the rim of the pan.
Place the pan in the freezer.
Fill a medium saucepan one-third of the way with water and bring to a simmer.
Place the chocolate, butter and peanut butter in a medium metal bowl over the simmering water and melt.
When melted, set the chocolate mixture aside, keeping it warm.
In a 4 1/2-quart bowl of an electric mixer, using the wire whip attachment, beat the egg yolks at medium speed until wellblended.
While continuing to beat, add 2 tablespoons of the sugar in a steady stream.
Remove the bowl from the mixer stand and place over a pot of hot water.
(The bottom of the bowl must touch the water.) Cook over medium-high heat, whisking constantly until the mixture is thick and tripled in volume, and registers 140 degrees F for 3 to 5 minutes on an instant read thermometer.
Remove the bowl from the heat and whisk the mixture until it is room temperature.
Using a large rubber spatula, gently fold in the reserved chocolate mixture.
In a chilled stainless steel medium bowl, using a hand-held electric mixer set at medium-high speed, whip the cream and 2 tablespoons of the sugar until soft peaks begin to form.
Using the rubber spatula, gently fold the whipped cream into the chocolate mixture.
Carefully scrape the mousse/terrine mixture into the prepared terrine pan.
Smooth the top with the rubber spatula.
Tap the pan on the counter to eliminate any air bubbles.
Cover the top of the terrine with the plastic wrap overhang.
Refrigerate for at least four hours until set.
Unmold the terrine------------------------.
Unfold the plastic wrap from the top of the chilled terrine, and use it to lift the terrine out of the loaf pan.
Invert the terrine onto a rack set on top of a cookie sheet.
Remove the plastic wrap from the terrine.
Glaze the terrine------------------.
Melt the chocolate and butter.
Whisk in the corn syrup.
Remove the melted chocolate from the double boiler and let cool for about 5 told minutes so it can thicken slightly.
Pour the glaze over the terrine, spreading it evenly over the entire terrine using an offset metal cake spatula.
Refrigerate until set, about 15 minutes.
Slice the terrine with a hot, dry knife into 9 even slices, and then again in half making a total of 18 pieces.
Place 3 pieces of terrine on each dessert plate.
Sprinkle with toasted peanuts over the top and sides of the terrine.
Garnish with sweetened whipped cream and chocolate curls.