Pre-heat the oven at 180°C
Heat olive oil in a large pan. Add chopped onion and garlic and sauté. Add chopped tomatoes, courgettes, butter beans, oregano, chilli flakes, salt, and pepper. Simmer for 15 minutes
Blanch spinach in boiling water or sauté, drain and roughly chop. Mix in ricotta, dill, basil, salt, and pepper
Melt butter in a small saucepan. Stir in the flour and cook for one minute while constantly stirring. Gradually whisk in the milk little by little, whisking well between each addition. Cook until thickened. Season with nutmeg, salt, and pepper
Break the lasagne sheets into smaller pieces and stir them into the tomato layer. Spoon the ricotta mixture on top and stir gently. Pour over the béchamel and add small dollops of pesto. Sprinkle grated cheese evenly on top
Bake for 25-30 minutes until golden and bubbling
