Heat oven to 350°F.
Combine all brownie ingredients in bowl until moistened. Spread into ungreased 9-inch springform pan. Bake 25-30 minutes or until set. Cool completely. Remove sides of springform pan.
Combine chocolate chips, whipping cream and 3 tablespoons butter in 2-quart heavy saucepan. Cook over low heat, stirring constantly, until chocolate melts.
Beat egg yolk in bowl. Stir about half
of chocolate mixture into egg yolk. Return egg mixture to saucepan. Continue cooking, stirring constantly, 1-2 minutes or until mixture comes to a boil. Remove from heat.
Pour chocolate mixture into bowl; stir in almond liqueur. Refrigerate, stirring occasionally, 1 1/2-2 hours or until completely cooled. Beat at medium speed until light and fluffy. Spoon or pipe topping onto brownie. Serve immediately or loosely cover and refrigerate up to 24 hours.
Cut into wedges to serve.
To cut through the truffle topping more easily, dip the knife in water before each cut. This keeps the truffle topping from sticking to the knife.