Cut the rice cakes and sausages into bite-sized pieces.
Chop the onion and garlic.
Heat olive oil in a pan and sauté the onion and garlic.
Add the sausage and rice cakes, and stir-fry together.
Pour in the milk and heavy cream, and bring to a simmer.
Season with gochujang, tomato sauce, sugar, salt, and pepper.
Add mozzarella cheese and mix everything well.
Simmer over medium-low heat until the rice cakes are fully cooked.