Perhaps you could adjust this recipe for the cinnamon flavoring?

CHART HOUSE CHOCOLATE MOUSSE PIE

FOR THE CRUST:
1 1/2 cups Oreo cookies (about 1/2 pound) broken into rough chunks; use the whole cookie, including the white cream filling
7 tablespoons unsalted butter, melted
FOR MOUSSE FILLING:
18 ounces (1 pound plus another 1/8 pound) Nestle's semi-sweet chocolate bits
6 egg yolks
5 egg whites
2 cups heavy cream

TO MAKE THE CRUST:
Place cookie chunks in the bowl of a food processor and process until you have crumbs. Add the melted butter and process again until well mixed.

Spray a 9-inch spring-form pan with nonstick cooking spray. Press the crumb mixture into the bottom of the pan and about 2 inches up the sides. Freeze to set while you prepare the mousse filling.

TO MAKE THE FILLING:
Place the chocolate bits in a heavy glass or ceramic bowl. Microwave for 1 minute, then stir and microwave again until the chocolate has melted completely. (If you prefer, you can place the chocolate in a bowl over a pot of water that is steaming - but not boiling - and let it melt, stirring occasionally.)

Stir the egg yolks into the melted chocolate.

Place the egg whites in a clean, dry mixing bowl. Beat, using a wire whisk, until soft peaks form. Fold the egg whites into the chocolate mix, one third at a time.

Place the cream in the mixing bowl you used for the egg whites and, using the wire whisk, beat the cream until it is stiff and not at all grainy. Fold the whipped cream into the chocolate mixture.

Pour the mousse into the reserved crumb crust. Freeze again until firm and set, about three or four hours.

To cut portions cleanly, use a sharp knife. Dip the knife into hot water and dry it off before you make each slice.

Source: Epicurious