Chocolate Orange Brownies

Heat oven to 350°. Line bottom of 8 inch square baking pan with aluminum foil. Butter foil and sides of baking pan generously. Melt chocolate and 4 tablespoons butter in small heavy saucepan over low heat, about 3 minutes. Stir to blend. Remove saucepan from heat; let stand until mixture is slightly cooled, about 2 minutes. Stir sugar into chocolate mixture until completely blended. Stir in egg until blended. Stir in grated orange zest and vanilla. Sift together flour, aching powder, and salt. Blend of them thoroughly into chocolate mixture. Scrape brownie batter into prepared baking pan, spreading evenly. Bake on center rack of oven until edges of brownies begin to pull away from sides of pan, about 18 minutes. Remove to wire rack to cool slightly, about 5 minutes. Invert pan to unmold brownies onto rack; peel off foil. Divide brownies into 4 equal squares. Place each square on a dessert plate; sprinkle each with 1/2 teaspoon Cointreau. Cover lightly with plastic wrap and reserve at room temperature until ready to serve. At serving time, beat heavy cream in chilled bowl with chilled beaters until soft peaks form. Top each brownie with a spoonful of whipped cream; garnish with a few strips of orange zest.