Put your pan on medium heat, pour in the oil and add onion, salt and pepper. Cook for about 5-10 minutes or until soft.
Then add in the minced garlic and cook until it is browned. Add in the tomato paste and mix until the onions and garlic are fully covered, then pour in the milk gradually, mixing until creamy.
This might get thick so thin it out with milk or water as desired. Then mix in red pepper flakes and more salt/pepper to taste.
Toast your bread and then add the onion mixture to the top. Top with fresh parsley and grated parmesan. Serve warm!