Difficulty: [3]
Peel the asparagus starting from the tip. Cook them for about 10 minutes in salted boiling water until tender. Drain and keep warm.
Shell the broad beans. Peel and chop the onion. Melt the butter in a sauté pan. Add the onion and gently sauté without browning, then add the broad beans, salt, and pepper.
Pour in 5 tablespoons of water and simmer for 8 to 10 minutes, until the beans are tender.
Preheat the oven to 150°C (thermostat 5).
Cut the puff pastries in half lengthwise. Place them in the oven to warm gently.
Prepare the saffron sauce at the last moment: In a small saucepan over a bain-marie, combine the egg yolks, 1 tablespoon cold water, salt, and pepper. Whisk with an electric mixer until smooth. Gradually add the diced cold butter, whisking constantly until the sauce thickens. Stir in the lemon juice and saffron filaments.
To serve, arrange the asparagus and broad beans on each puff pastry base, sprinkle with chopped chervil, replace the tops, and serve immediately.
