Gather and prepare your ingredients. Preheat the oven to 190°C/170°C fan.
Place a large heavy-bottomed saucepan over medium-high heat. Add the olive oil and onion with a sprinkle of salt. Cook, stirring often, for 4-5 minutes, until softened and reduced.
Add the mushrooms and cook, stirring often, for 10-12 minutes, until reduced and darkened.Allow all of the liquid from the mushrooms to evaporate before proceeding to the next step.
Add the garlic, paprika, chilli flakes, miso and tomato puree and cook, stirring occasionally, for 2-3 minutes, until darkened and fragrant.
Add the tomato passata and cook for a further 10-12 minutes, until darkened and reduced.
Add the lentils, spinach and most of the basil. Cook for 1-2 minutes, just until the greens have wilted.Reserve a few leaves of basil for garnish.
Assemble the lasagna. Layer ¼ of the lentil mixture and dot with cottage cheese.The cheese will melt as it bakes, so there is no need to spread it out, just evenly space it out.
Sprinkle with mozzarella and parmesan. Top with lasagne sheets and repeat twice more. Finish with a final layer of lentils, mozzarella cheese and parmesan.
Place into the preheated oven and bake for 30-35 minutes, until golden brown and bubbling. Allow to cool for 5-7 minutes before slicing.