Source: Desert Candy
Chocolate-Peanut Butter Mousse Tarts
Who doesn't love a peanut butter cup? The recipe calls for a total of 3 cups whipped cream, which means you will want to start with 1 1/2 cups of heavy cream and whip it to stiff peaks. I find it is easiest to transfer the mousses to the freezer when working with them, so that they firm up quickly, so you may want to clear out some freezer space before starting.
1 1/2 cups chocolate cookie crumbs (like Nabisco Famous Wafers)
4 Tbsp. melted butter
chocolate mousse layer:
4 oz bittersweet chocolate, finely chopped
1/3 cup milk
3 Tbsp. sugar
2 Tbsp. cocoa powder
1 cup whipped cream
1 splash rum (optional but highly recommended)
peanut butter mousse layer:
3/4 cup creamy peanut butter
4 oz. cream cheese, softened (low fat is fine)
1 cup confectioners sugar
1/4 tsp. salt
2 cups whipped cream
1 cup sugar
1/2 cup water
4 oz bittersweet chocolate
1. Combine the cookie crumbs and melted butter. Press into the bottom of a 10" springform pan or 8 round molds set on a parchment-lined baking sheet. Refrigerate until ready to use.
2. For the chocolate mousse: Finely chop the chocolate and place in a small bowl. Place the milk, sugar, and cocoa in a small saucepan and stir to combine. Heat the milk mixture until simmering, then pour over the chopped chocolate, add the rum. Stir the chocolate mixture gently until everything is melted and combined. Stir the chocolate mixture until it is no longer hot to the touch (but don't wait so long so that the chocolate hardens). Fold in the whipped cream, then refrigerate the mixture.
3. In a bowl, combine cream cheese, peanut butter, sugar, salt until smooth. Fold in the whipped cream. Keep in the refrigerator.
4. Spread the chocolate mousse in the bottom of your springform pan, or divide it between the small molds. Top with the peanut butter mousse, gently smoothing the top. Transfer to the freezer to set for at least one hour (I find it is easier to work with the mousses from the freezer, but you can use the refrigerator. Also, if you're making minis, it will be easiest to unmold them if they are completely frozen).
5. Once the edges of the mousse are firmly set, unmold the tart by running a hot knife around the edge of the pan/mold, then remove the sides of the pan/mold. Return the mousse to the freezer while you make the glaze.
6. Make the glaze: place the sugar, water, and chocolate in a small saucepan and clip a candy thermometer on the side. Bring to a boil and let boil until the mixture reaches 234F, about 5 minutes. Meanwhile, take your mousse out of the freezer and place on a rack. Remove the glaze from the heat, and give the chocolate glaze one stir just to cool slightly, then pour the glaze immediately over the mousse tarts. You have to work very quickly as the glaze will begin to harden. If it hardens early, it may be less than pretty, but don't worry it will still taste good.
7. Store in the fridge until serving. If you have a large mousse tart, cut slices with a hot knife. The tart may begin to break down after 2 days in the fridge, simply freeze any leftovers and thaw in the refrigerator before serving.
Lighten Up Tip: Instead of 3 cups whipped cream you can use a lightened whipped cream: whip one cup cream to stiff peaks. Whip one egg white with one pinch of sugar until it is shiny and holds stiff peaks, fold the egg white into the whipped cream. Use in the recipe as directed.
The Molds: To make the miniature mousse tarts, it's easiest if you use mini springform pans (2 or 3" diameter). However, they can be expensive, so you can also use ring molds, available at pastry supply stores, or simply use a tube of piping. If using piping, wash it well and line the inside with some parchment paper.