Preheat oven to 190 °C (170 °C fan-forced).
Heat a large, non-stick frying pan over a medium-high heat. Add mince and garlic and cook until mince is browned all over, breaking up any large pieces with a wooden spoon.
Add carrots and zucchini and stir over heat for a further 2 minutes.
Stir in tomatoes, water, herbs, stock cube and half the passata (reserve the remaining passata for topping). Bring to the boil, then reduce heat.
Simmer uncovered for 15 minutes or until thickened slightly. Stir in peas and remove from heat.
Lightly spray a large rectangular ovenproof dish (12-cup capacity) with cooking oil. Place a layer of lasagne sheets over base of dish and spread with one-third of the mince mixture.
Repeat the layers of lasagne sheets and mince mixture twice more. Cover with remaining lasagne sheets and spread with the reserved passata.
Dollop heaped teaspoons of ricotta over passata. Sprinkle with parmesan. Spray a piece of cooking foil with cooking spray. Place spray-side down over lasagne.
Place dish on oven tray. Bake in preheated oven for 45 minutes.
Remove foil covering and bake for a further 15 minutes, or until lasagne sheets are tender and top is lightly browned. Allow lasagne to rest for 5 minutes, then cut into squares and serve with salad leaves.