Preheat oven to 180 °C fan bake. Check your avocado is ripe. Spray a baking dish with oil spray.
Make filling
Finely chop 4 cups baby spinach. Heat 1 tbsp olive oil in a large frypan and add spinach, cook until wilted. Transfer to a plate to cool. Reserve the pan. Grate 1 cup cheese and ¼ cup parmesan cheese. Peel and mince 2 cloves garlic. Combine 500 g ricotta cheese, half the cheese, the parmesan, 2 egg, half the garlic and cooled spinach to a large bowl. Season salt and pepper to taste.
Prep sauce
Peel and finely slice 1 brown onion. Heat 1 tbsp olive oil in the reserved pan over medium-high heat. Add onion and the remaining half of the garlic, and cook for 2-3 minutes until translucent. Add 800 g crushed tomatoes. Stir, reduce heat to medium, simmer for 5 minutes. Stir through 2 tsp Italian herbs and season with salt and pepper. Set aside.
Prep cannelloni
Spread a bit of the sauce on the base of the prepared baking dish. Lay out 400 g fresh lasagna sheets and spoon a line of the filling along the centre of each. Roll up the sheets into a tube and place them on top of the sauce in the baking dish, seam side down one by one. Pour over the remaining sauce, covering all the tubes.
Bake cannelloni
Cover with foil, then bake for 25 minutes. Remove the foil, and sprinkle over the remaining half of the cheese. Return to oven for 10 minutes until cheese is melted.
Make salad
Adding to a large bowl as you go - peel, deseed and dice 1 avocado. Slice 2 tomato into wedges. Add 2 cups mixed salad leaves and toss to combine.
To serve
Divide the spinach and ricotta cannelloni between plates with the garden salad on the side.