Preheat the oven to 220C, fan-forced. Line an oven tray with baking paper. Cut the tomato into wedges. Cut the onion into thin wedges. Put the tomato and onion on the lined tray. Drizzle with 1 tbs olive oil and scatter over half the Italian seasoning*. Season with salt and pepper and toss to coat. Roast for 15 mins or until tender.
Step 2 — Cook spaghetti
Meanwhile, bring a medium saucepan of salted water to the boil for the spaghetti. Crush or finely chop the garlic. Finely chop the oregano leaves, discarding the stems. Thinly slice the chicken. Cook three-quarters of the spaghetti* in the pan of boiling water for 12 mins or until al dente. Reserve 125ml (½ cup) cooking water, then drain the spaghetti.
Step 3 — Cook chicken
Meanwhile, heat 1 tbs olive oil in a medium deep frypan over medium-high heat. Cook the chicken and garlic, stirring, for 3-4 mins until the chicken is browned and cooked through.
Step 4 — Make sauce
Add the tomato and onion, tomato paste, reserved cooking water, 1 tbs balsamic vinegar and 1 tsp sugar to the chicken and cook, stirring, for 1-2 mins until warmed through (see Make it yours).
Step 5 — Serve up
Add the spaghetti to the sauce and toss to combine. Remove the pan from the heat. Taste, then season with salt and pepper. Divide the spaghetti among bowls, scatter over the oregano and enjoy!
Step 6 — Make it yours
Like your sauce a bit thinner? Just add a little more water to the pasta sauce.