Bring a medium saucepan of salted water to the boil for the spaghetti. Finely chop the onion. Coarsely grate the cheddar.
Step 2 — Cook spaghetti
Add three quarters of the spaghetti* to the pan of boiling water (if you're tempted to throw in all the spaghetti, just note the dish won't be as saucy). Cook, stirring occasionally, for 12 mins or until al dente. Reserve 125ml (½ cup) cooking water, then drain.
Step 3 — Start sauce
ADD BACON OPTION Meanwhile, heat 2 tsp olive oil in a medium deep frypan over medium heat. Cook the onion and bacon, stirring, for 4-5 mins until the onion is soft and the bacon is crisp.
Step 4 — Finish sauce
Gradually add three-quarters of the cream* to the onion mixture and stir until combined. Bring to a simmer and cook, stirring regularly, for 2-3 mins until smooth and slightly thickened. Add the cheddar cheese and 2 tsp pepper and garlic seasoning (reduce the seasoning for a milder pepper kick) and stir until melted and combined.
Step 5 — Add spaghetti
Add the spaghetti to the sauce. Gradually add the reserved cooking water, stirring constantly, until the sauce coats the pasta and looks slightly glossy. Taste, then season with salt. Remove from the heat.
Step 6 — Toss salad and serve
Shave the parmesan with a vegetable peeler. Put the salad leaves and parmesan in a large bowl, add the maple and mustard dressing and toss to coat. Taste, then season with salt and pepper. Divide the spaghetti among bowls. Scatter with the remaining pepper and garlic seasoning and serve with the salad.