Preheat the oven to 375°F (190°C). Line a sheet pan with parchment paper.

In a food processor or blender, combine the ricotta, feta, olive oil, honey, and lemon zest. Blend until smooth, light, and creamy. Season with salt and pepper to taste.

On a lightly floured surface, roll out the puff pastry slightly to even the edges, if needed. Transfer to the prepared sheet pan. Spread the whipped ricotta over the center of the pastry, leaving a 1-inch/2.5 cm border around the edges.

In a bowl, toss the zucchini slices with a drizzle of olive oil, salt, and pepper until evenly coated. Layer them over the ricotta mixture in slightly overlapping rows. Brush the exposed pastry edges with the beaten egg.

Bake for 25 to 30 minutes, or until the pastry is deeply golden and puffed.

Remove from the oven. While still warm, drizzle with hot honey, sprinkle with crushed pistachios, and finish with flakey salt.

Serve warm or at room temperature, cut into squares.