Cut the eggplant in half lengthwise, then slice diagonally into 1cm pieces. Mince the garlic.

Drain the canned mackerel and roughly flake it.

Boil water in a pot, add salt (not listed in ingredients), and cook spaghetti slightly shorter than the package instructions. Reserve 2 tbsp of pasta water and drain the rest.

Heat olive oil in a pan over low heat, add garlic and red chili, and sauté until fragrant. Add eggplant and cook until softened, then add mackerel and stir quickly.