Cook the sausages in a large pan (or an air fryer) for about 10 minutes.
In a small mixing bowl, mix all the ingredients for the pink sauce.
Put the lasagne sheets into a pan of with warm water one at a time to prevent them sticking together. Let them sit for 5-6 mins until soft enough to roll up (but not fully cooked).
(Optional) Wipe any dirt off the mushrooms and spinach and chop into small pieces.
In a large rectangular casserole dish, add a layer of sauce to the bottom.
Gently take a lasagna sheet, place a cooked sausage in between, and place the lasagna roll down in the casserole dish.
Repeat for the rest of lasagna sheets and sausages, until the bottom of the casserole dish is covered.
Preheat the oven at 400°F (200°C).
Layer any optional veggies on top of the canelloni rolls and top with a handful of cheese and 2-3 spoonfuls of pink sauce until covered.
If you have any lasagna sheets and sausages left (depending on the size of your casserole dish), make a second layer of sausages in lasagna sheets.
Top the cannelloni rolls with the pink sauce mix.
Sprinkle the top layer with shredded cheese, added liberally.
Place in the oven for 25-30 minutes or until the cheese on top looks cooked and golden brown.
Serve while warm.