Roasted Balsamic Red Onion and Cherry Tomato Pasta

Roasted Balsamic Red Onion and Cherry Tomato Pasta

This one is a proper weeknight hero. We keep coming back to it because roasting the red onions low and slow with balsamic turns them into something almost jammy and sweet, and when you tumble in the cherry tomatoes they burst into this glossy, sticky sauce that coats every strand of pasta. It's the kind of recipe that smells absolutely incredible while it's in the oven and makes everyone wander into the kitchen asking what you're cooking. Yeah, it takes about 65 minutes, but most of that is hands-off oven time while you do your thing. Make this tonight and you will not regret it.

Cook: 65 min
Serves 2

Before You Start

  • Preheat oven to 180°C fan
  • Roasting tin
  • Foil for covering tin

Ingredients

  • 4 medium red onion
  • 3 tbsp olive oil
  • 3 tbsp balsamic vinegar
  • 2 tbsp water
  • 200g cherry tomatoes good quality
  • 4 sprigs of thyme
  • Salt & pepper to taste
  • 250g spaghetti
  • simple green salad to serve

Method

1

Start the roasting process

  • Peel the onions, cut off both ends and cut the onions into wedges
  • Spread the onions around in the tin, drizzle over 2 tbsp of the olive oil and 2 tbsp of the balsamic vinegar and season with a little salt and pepper
  • Add the water to the tin, cover the tin with foil, put the tin in the oven and roast for 30 minutes
2

Finish the roasting process

  • Halve the cherry tomatoes
  • Remove the tin from the oven
  • Add the tomatoes to the tin around the onions
  • Drizzle over the remaining olive oil and balsamic vinegar and sprinkle over the thyme sprigs
  • Put the tin in the oven, turn the oven down to 180˚C, fan setting and roast for a further 30 minutes uncovered
3

Prepare the pasta

  • When the onions and tomatoes have 10 minutes left in the oven, cook the spaghetti according to packet instructions (approx 9 minutes) in a big pot of boiling salted water
4

Finish the dish and serve

  • Remove the tin from the oven and set it down on a heat proof surface
  • Remove the thyme sprigs
  • Add a ladle of pasta water to the tin, stir to deglaze and create a silky saucy consistency
  • Drain the pasta, add the pasta to the tin and stir to coat and cover
  • Twist the pasta into bowls, dress with a simple green salad or some fresh herbs, season with a little salt and pepper and serve immediately

Tips & Variations

  • Get ahead on the roasting: You can roast the onions and tomatoes in advance and keep them in the fridge for up to 3 days. When you're ready to eat, just cook your pasta and toss everything together. Makes weeknight dinners seriously fast.
  • Boost the richness: We love stirring a big spoonful of vegan cream cheese or cashew cream through the pasta just before serving. It makes the sauce extra silky and rounds out the acidity of the balsamic beautifully.
  • Add some crunch on top: A handful of toasted pine nuts or some crispy breadcrumbs fried in olive oil scattered over the top just before serving takes this from great to genuinely restaurant-level. Ian is obsessed with the breadcrumb move.

Why This Works

The trick here is patience with the roasting. Covering the onions with foil for the first 30 minutes steams them until they're completely tender, then uncovering them lets all that balsamic and olive oil reduce down into a sticky, caramelised glaze. That depth of flavour is what makes this feel way more special than a regular tomato pasta, and it costs almost nothing to make.