To prepare the mushroom filling, add oil to large pan on stove top and set heat to medium/medium low. Add mushrooms and garlic and cook until brown (this could take anywhere from 8 to 20 minutes depending on your stove). Do not let the garlic burn! I'd rather take the time to let the the mushrooms brown on a lower heat than have burnt, acrid tasting garlic. When mushrooms are done, remove to a separate bowl and set aside.
To prepare the sausage filling, saute sausage meat in large pan on medium heat in the small amount of oil, breaking up the meat into small pieces as it browns. Drain any oil from pan and when meat has lost its pink color, add 1/4 cup of tomato sauce. Stir to combine and remove to a separate bowl and set aside.
To make the cheese mixture combine all cheese ingredients in medium size bowl. You're now ready to assemble all the components and start rolling your egg roll cannellonis.
Prep the bottom of a large baking dish with 1/3 cup tomato sauce. Pre heat oven to 375 degrees. On cutting board or work surface place one egg roll strip and in the center add 2 or 3 cooked mushrooms with garlic. This is layer one.
Top mushrooms with about 2 teaspoons ricotta mixture.
Now add about 2 teaspoons sausage mixture.
Top with a basil leaf, and sprinkle with a pinch or two of mozzarella or parmesan and roll this baby up. Fold the back side of the egg roll over the top and the front side to meet the back. You should have about 1 1/4 inch overlap. Place rolled cannelloni in baking dish, seam side down.
Continue rolling. The assembly and rolling go quickly and by the time you're half way through, you'll have it down to a science. Top the cannelloni with most of the remaining tomato sauce and top with mozzarella and parmesan cheese.
Bake uncovered for 35 minutes. Let cool a bit and garnish with fresh basil. Serve warmed tomato sauce on the side.