Step 2

Put the carrot, onion and zucchini in a saucepan with the water, bring it to a boil and cook for 5–7 minutes, until soft. Add the lentils and the crumbled bouillon cube, if using, and simmer, stirring now and then, until the lentils are soft and most of the water has been absorbed, about 20 minutes. Season with the ground coriander and salt.

Step 3

Blanch the spinach in a large pot of boiling water for 1 minute, until wilted. Lift it into a colander, squeeze out the water and keep it on a plate.

Step 4

Cook the lasagna noodles in the same water until just tender, as the package directs. Drain them and lay them flat on an oiled sheet pan so they don't stick.

Step 5

Make the white sauce: melt the vegan butter in a saucepan, stir in the flour, then gradually whisk in the soy milk. Add the mustard and vinegar. Cook, stirring continuously, until smooth and thickened.

Step 6

Layer the lasagna noodles, lentil mixture, spinach, and white sauce alternately in a baking dish about 8 × 10 inches (20 × 25 cm), finishing with a layer of white sauce. Bake for 25 minutes until golden and bubbling.