Combine hot coffee and liqueur in a thermos; screw on lid. Stir together whipping cream, powdered sugar, and vanilla bean paste in a 16-ounce jar with a tight-fitting lid. Cover and chill in ice at least 15 minutes. When ready to serve, shake jar 8 to 10 minutes or until cream is whipped. Pour coffee into mugs, and top with whipped cream mixture. Garnish, if desired.