01 - Preheat the oven to 400°F. Line a baking tray with parchment paper.
02 - Roll out the puff pastry on a lightly floured surface and cut into 12 equal rectangles. Arrange the rectangles on the prepared tray, sprinkle evenly with granulated sugar, then place a second sheet of parchment paper and another baking tray on top to prevent excessive puffing.
03 - Bake for 15 to 20 minutes until the pastry is crisp and golden brown. Transfer to a wire rack and let cool completely.
04 - In a mixing bowl, whisk the ricotta until smooth. Add the powdered sugar, lemon zest, lemon juice, and vanilla extract, then mix thoroughly until well combined.
05 - In a separate bowl, whip the heavy cream to stiff peaks. Gently fold the whipped cream into the ricotta mixture in two additions until fully incorporated. Refrigerate until ready to assemble.
06 - Spread or pipe a generous layer of lemon ricotta cream onto six of the pastry rectangles, then place a second rectangle on top of each to form the layered mille feuille.
07 - Dust the top layer of each assembled mille feuille with powdered sugar and finish with a touch of fresh lemon zest. Serve immediately for the best texture contrast.