On a lightly floured surface, roll each puff pastry sheet into a 12-inch square. Using an 11-inch heart pattern, cut each pastry into a heart shape. Place on greased baking sheets. Bake at 400 degrees for 12–15 minutes or until golden brown. Remove to wire racks to cool.
Meanwhile, combine milk and pudding mix until thickened. In a mixing bowl, beat cream and 1/2 teaspoon of vanilla until stiff peaks form. Carefully fold into pudding. Split puff pastry hearts in half. Place one layer on a serving plate. Top with a third of the pudding mixture. Repeat twice. Top with remaining pastry.
In a bowl, combine confectioners' sugar, water, almond extract and the remaining vanilla until smooth. Spread over top.
Melt chocolate chips and shortening; pipe in diagonal lines in one direction over frosting. Beginning 1 inch from side of heart, use a sharp knife to draw right angles across the piped lines. Refrigerate until set.