Air Fryer Recipe

Caramelised Onion Tartlets

  • Prep: 10 min
  • Cook: 15 min
  • Total: 25 min
  • Serves: 4
  • Category: Snacks
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Caramelised Onion Tartlets

Caramelised onion tartlets are a delightful treat that combines buttery, flaky pastry with the rich, sweet flavour of slow-cooked onions.

Ingredients

  • 2 large onions, thinly sliced
  • 2 tablespoons of olive oil
  • 1 tablespoon of balsamic vinegar
  • 1 tablespoon of brown sugar
  • 100g of goat cheese
  • 1 sheet of puff pastry
  • Salt and pepper to taste
  • Fresh thyme for garnish (optional)

Method

  1. In a large pan, heat the olive oil over medium heat. Add the sliced onions and a pinch of salt.
  2. Cook slowly for about 15-20 minutes, stirring occasionally, until the onions are soft and beginning to brown.
  3. Add the balsamic vinegar and brown sugar to the pan, stir well, and continue to cook for another 5-10 minutes until the onions are sticky and deeply caramelised.
  4. Remove from heat and set aside to cool slightly.
  5. Preheat your air fryer to 180°C (350°F).
  6. Roll out the puff pastry on a lightly floured surface and cut into small circles to fit your tartlet moulds or your air fryer's basket.
  7. In each pastry circle, place a generous spoonful of the caramelised onion mixture. Top each with a slice of goat cheese.
  8. Carefully place the tartlets into the air fryer basket.
  9. Cook for 10-12 minutes or until the pastry is golden and puffed, and the cheese is melted and bubbling.
  10. Garnish with a sprig of fresh thyme and serve warm.

Why this works in an air fryer

Air-fryer convection drives moisture off the pastry quickly, so the butter layers steam and lift before the onion topping can make the base soggy. Pre-caramelising the onions removes water and concentrates sugars; cooling them slightly protects the pastry fat from melting too early.

Equipment notes

Assumes a 5–6 litre basket holding 4–6 small tartlets in one layer with space between them; in a single-drawer model cook in batches for best lift, while in a dual-zone air fryer use the upper/hotter zone if applicable, rotate or swap drawers halfway, and expect the lower-loaded drawer to need 1–2 minutes longer.

Common pitfalls

  • Pastry looks pale and flat at 12 minutes? The onions were too wet or added hot; reduce the onion mix until sticky, cool it before topping, and give the tartlets 2–3 extra minutes at 180°C.
  • Edges brown before the centre puffs? The pastry circles are too thin or too close to the heating element; cut them slightly thicker, lower to 170°C, and cook 2 minutes longer.
  • Cheese slides off and leaks into the basket? The onion mound is domed too high; flatten the filling, leave a 5mm pastry rim, and use a smaller piece of goat cheese.
  • Bases are greasy or limp underneath? The basket or moulds blocked airflow; use perforated silicone/metal tartlet moulds where possible and lift the tartlets onto a rack for 2 minutes after cooking.

Variations & substitutions

  • Use red onions for a sweeter filling; they release more moisture, so cook the onion stage a few minutes longer until properly jammy.
  • Swap goat cheese for blue cheese; it melts faster and can split, so add smaller pieces and check from minute 8.
  • Use ready-rolled shortcrust instead of puff pastry; it will not rise as much and usually needs 1–2 extra minutes for a crisp base.
  • Add a thin layer of fig chutney under the onions; keep it scant because extra sugar browns quickly in the air fryer.

Storage & reheating

Keep cooled tartlets in an airtight container in the fridge for up to 3 days, then reheat in the air fryer at 160°C for 4–6 minutes until the pastry crisps again.

Nutrition

Calories: 250

Equipment you'll need

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