Step 1 of 4

Roast the vegetables until they color

Heat the oven to 425°F. Toss the eggplant, zucchini and pepper with 4 tablespoons of the oil and a teaspoon of the salt, spread across two trays and roast for 30 minutes, turning once, until browned at the edges and no longer releasing steam.

— Wait for the browning. Vegetables pulled out while still pale are still full of water, and that water ends up as a puddle under the lasagne.