Preheat the oven to 350.
Cut a tiny lengthwise slice from the zucchini then rotate it 90 degrees so that the cut side is down. This will make it easier to slice the rest of the zucchini lengthwise into ¼ inch thick, even strips. Too thin, they’ll dry out in the oven. Too thick, they won’t roll properly.
Oil both sides of each strip and arrange in a single layer on cookie sheet. Sprinkle with salt and pepper.
Bake for 15 minutes, until starting to color. Flip and bake another 10 minutes. Each slice should be golden brown and flexible. Let cool for a few minutes.
Spread the tomato sauce in the baking dish.**
Place about a T of ricotta at the end of a zucchini slice, then roll up. Place in the baking dish, seam side down, and repeat with remaining slices.
Bake for 10 minutes, just until warmed through.
Carefully scoop each rollatini and its sauce onto a plate and serve.