Put the red peppers, heavy cream, garlic, Italian seasoning, kosher salt, pepper, and crushed red pepper flakes in a food processor or blender. Blend until smooth.
Prepare the rest of the ingredients. Preheat the griddle to medium heat for a few minutes. Add some cooking oil, the thawed tortellini, cover with a 9×13 foil pan or melting dome and squirt a little water on the griddle under the dome.
Cook 2 to 3 minutes total, flip them around halfway through, add more water, and cover again (if using the foil pan use caution as it will be hot). Set the pan or melting dome aside.
Add a little more olive oil and the onion to the tortellini. Cook 2 to 3 minutes, mixing together with hibachi spatulas.
Add the spinach and shrimp plus season with kosher salt, pepper, and crushed red pepper flakes, and more cooking oil if needed. Cook 2 to 3 more minutes. Then pour the red pepper sauce over top, mix it all together for 1 to 2 more minutes. Serve with parmesan cheese sprinkled over top.Note: The sauce will thicken on the griddle as it cooks.