Cut spinach into 3cm pieces, slice onion thinly, cut sausages into bite-sized pieces, and slice garlic.

Heat olive oil in a pan, add garlic, and sauté until fragrant. Add sausages and onion, cook until softened, then add spinach and stir-fry.

Add canned tomatoes, ketchup, and salt and pepper to the pan. Cook for 10 minutes, stirring occasionally.

Place spaghetti in a microwave-safe container, add salt and water, and microwave at 600W for 4 minutes longer than the package instructions.