Sunday supper: Broccolini and Asparagus White Lasagna

Serves 8 to 10.

Note: Alex Aimassi, a chef at the London-based restaurant Mildreds, first developed this recipe as a lunchtime special, though it’s now one of the most popular dishes and flies out of the door whenever they make it. If using dried lasagna sheets, add a splash of water between layers of pasta when assembling to stop it from drying out. From “Mildreds Vegetarian: Vegetable Focused, Delicious Food” (Hamlyn, 2024).

For the caramelized onion:

• Splash of light cooking oil, such as vegetable or sunflower

• 6 white onions, finely sliced

• 1 tbsp. superfine sugar

For the white sauce:

• 1 white onion, cut into quarters

• 6 cloves garlic

• 3 bay leaves

• 1 3/4 lb. Broccolini

• 9 oz. (18 tbsp.) butter

• 2 bunches of basil leaves, chopped

For the lasagna:

• 1 1/2 lb. asparagus spears, trimmed and woody ends removed

• 1 lb. Broccolini

• 1 1/2 lb. fresh lasagna sheets (see Note)

• 10 oz. Cheddar cheese, grated

• Salt

Directions

For the caramelized onion: Heat the oil in a saucepan over medium heat, add the onions and cook for 15 minutes, stirring, until they begin to color. Add the sugar and continue to cook for 15 to 20 minutes, stirring occasionally, until the onions are dark golden brown and caramelized. Remove from the heat and set aside.

For the white sauce: Meanwhile, bring the milk, onion, garlic and bay leaves to a simmer in a saucepan over medium heat. Remove from the heat and set aside for 10 minutes for the flavors to infuse. Cook the Broccolini in boiling water for 3 minutes until tender. Drain and roughly chop. Melt the butter in a saucepan, add the flour and stir together to form a roux. Strain the milk into the pan and whisk together to form a smooth sauce. Add the Broccolini and basil to the sauce and blend with a stick blender until the sauce is smooth.

Preheat the oven to 375 degrees. To layer the lasagna, add a splash of water to the bottom of a 9- by 13-inch rectangular ovenproof dish, then arrange a layer of lasagna sheets on top. Spoon over half the caramelized onion, Broccolini, asparagus and half the grated cheeses, then layer with a third of the white sauce. Repeat the layers of pasta, filling and sauce, finishing with a third layer of pasta and a final layer of white sauce. Bake for 40 to 50 minutes, until the pasta is cooked and the top is golden brown (if the lasagna is browning too much during cooking, cover it with foil).