01 - 
                In a large skillet, cook the chopped bacon over medium heat until crisp. Transfer to a paper towel-lined plate to drain.
              
              
              
                02 - 
                Using the reserved bacon fat in the skillet, sauté the sliced onions with a pinch of salt and black pepper over medium-low heat for 25–30 minutes, stirring occasionally. Add apple cider and continue cooking for 5 minutes until onions are deeply golden and soft.
              
              
              
                03 - 
                Preheat the oven to 200°C. On a lightly floured surface, gently roll out each puff pastry sheet. Lay each puff pastry onto a parchment-lined baking tray. Score a 2.5 cm border around the edges and prick the center section all over with a fork.
              
              
              
                04 - 
                In a bowl, combine ricotta, pumpkin purée, a pinch of salt, and black pepper until smooth. Evenly spread the ricotta mixture within the scored pastry borders. Spoon caramelized onions over the base, followed by mozzarella and crumbled bacon.
              
              
              
                05 - 
                Scatter fresh sage leaves across the filling. Beat eggs with water to make an egg wash, then brush it around the pastry borders.
              
              
              
                06 - 
                Bake in the preheated oven for 25–30 minutes or until the pastry is puffed and golden brown.
              
              
              
                07 - 
                Allow tart to cool slightly, then sprinkle generously with grated Parmesan cheese. Serve warm or at room temperature.