Butter and flour a 9-inch springform pan. Line with wax paper; butter paper. Set aside.
Process 1/2 cup whole almonds and 2 tablespoons sugar in a food processor until ground. Spoon into a bowl. Set aside.
Process remaining 1/2 cup whole almonds and oil in a food processor 3 minutes or until a thick paste forms, stopping often to scrape down sides.
Bring butter and whipping cream to a boil in a heavy saucepan over medium heat. Remove from heat, and whisk in chocolate until smooth. Stir in almond mixtures; cool slightly.
Beat egg whites at high speed with an electric mixer until foamy. Add 1/3 cup sugar, 1 tablespoon at a time, beating until stiff peaks form and sugar dissolves (2 to 4 minutes).
Beat egg yolks until thick and pale. Gradually add chocolate mixture to yolks, beating until blended. Fold in one-third of egg whites. Gradually fold in remaining egg whites. Pour batter into prepared pan.
Bake at 350° for 35 minutes or until almost set. Cool on a wire rack. Run a sharp knife around edges to loosen. Remove sides of pan. Cover and chill up to 3 days.
Beat cream at medium speed with an electric mixer until foamy; gradually add 2 tablespoons sugar, beating until soft peaks form. Stir in liqueur. Serve with torte; garnish, if desired.