Boil the pasta in a pot filled with salted water. Then, drain the water and set the pasta aside.
In a skillet, add olive oil, onion, and garlic on medium heat. As the onions get translucent, add spinach, butter, salt, and basil-garlic seasoning, oregano, and red pepper together. Cook for 2-3 minutes.
Mix cornstarch with water to dilute it and pour it into the sauce until you get desired consistency.
Add shrimp and crab meat. Stir and cook for another minute.
Add the cooked pasta to this sauce and mix so that it gets covered with the sauce. Garnish it with parmesan cheese and serve.