Saute spinach, onion and mushroom until soft and set aside to cool.
In a large bowl add ground meat, bread crumbs, oregano, parmigiano, and beaten egg and mix until well incorporated.
Place meat mixture between sheets of parchment paper and using hands or a rolling pin, flatten out until you have made a large rectangle about 1/2 inch thick.
Layer ricotta cheese and all other ingredients evenly over surface of the meat.
Using the parchment paper and both hands begin tightly rolling meat until you have made a log.
Refrigerate for 1 hour.
Remove from fridge, cut into 1 or 2 inch slices.
Squeeze slice firmly with your hand to make sure it does not separate then fry with some oil in a hot pan for 2 minutes each side.
In a baking tray, add some tomato sauce and the fried meat slices.
Top with more sauce and grated cheese then bake covered for 35 minutes at 375F and uncovered for an additional 10 minutes.
Remove from oven, top with some fresh chopped basil and serve.