Step 1

Heat a saucepan over medium-low heat. Spray with oil. Cook the onion, carrot and celery, stirring occasionally, for 6 minutes or until soft. Add garlic. Cook, stirring, for 1 minute.

Step 2

Add the tomato paste. Cook, stirring, for 2 minutes. Add the tomato and lentils. Cook, stirring occasionally, for 10 minutes or until mixture thickens. Set aside to cool slightly.

Step 3

Preheat oven to 180ºC. Spray a 2L (8-cup) capacity baking dish with oil. Combine the ricotta, milk and egg in a bowl.

Step 4

Place 80ml (1/3 cup) of lentil mixture in the dish. Top with 1 lasagne sheet, half the remaining lentil mixture, half the zucchini and one-third of the ricotta mixture. Continue layering with another lasagne sheet, remaining lentil mixture, remaining zucchini and half the remaining ricotta mixture. Top with the remaining lasagne sheet and ricotta mixture. Sprinkle with parmesan. Bake for 30 minutes.