1. Heat oven to 400 degrees. Roll pastry to 1/8 inch thick; cut out four 5-inch squares. Place on a parchment-lined baking pan; bake about 15 minutes, until golden. Remove from oven; set aside to cool.

2. Place butter, sugar, vanilla, and salt in a saute pan over medium heat. Cook, stirring frequently, until butter and sugar are melted and combined, about 5 minutes. Stir in cream until mixture is smooth. Add bananas; gently stir until coated. Remove from heat.

3. Using a paring knife, remove and discard a 2-inch square from top center of reserved pillows; keep bottom intact. Fill with banana mixture. Dust with confectioners' sugar, and garnish with chocolate shavings. Serve.