Cut the tomato into 1cm cubes, mince the onion, and crush the garlic clove, removing its core.

Boil water in a pot, add salt, and cook the spaghetti slightly shorter than the package instructions.

Heat olive oil and garlic in a pan over low heat until fragrant. Add onion and tuna, cooking over medium heat until softened.

Add milk, cream, salt, and pepper to the pan, simmering over medium-low heat until the milk reduces. Add tomato and cook until softened.

Combine the cooked spaghetti with the sauce, mixing quickly to coat evenly.