Earthy beetroot and sweet, slowly softened red onions sit on crisp puff pastry with thyme and tangy goat cheese. It makes a colourful lunch from a late-summer beetroot harvest and is just as good served warm as part of a picnic.
Ingredients
- 500g, trimmed Raw beetroot
- 2 medium, thinly sliced Red onions
- 2 tbsp, divided Olive oil
- 1 tbsp Balsamic vinegar
- 5 sprigs, leaves picked Fresh thyme
- 1/2 tsp, divided Fine salt
- 1/4 tsp Black pepper
- 320g sheet, made with butter and without lard Ready-rolled puff pastry
- 100g, crumbled Soft goat cheese
- a little, for dusting Plain flour
Equipment
Roasting tray · Kitchen foil · Frying pan · Baking sheet · Sharp knife
Method
- Heat the oven to 200°C / 180°C fan. Scrub the beetroot, trim the tops and roots, and wrap the whole roots loosely in foil. Roast on a tray for 45–60 minutes, depending on size, until a skewer slides through the centre. Leave until cool enough to handle, then rub off the skins and cut into 1cm wedges. Wear gloves if you want to avoid staining your hands.
- While the beetroot roasts, heat 1 tbsp oil in a frying pan over low heat. Add the sliced onions and 1/4 tsp salt. Cook gently for 20–25 minutes, stirring often, until soft and golden, not dark brown. Stir in the balsamic vinegar and half the thyme for the final 2 minutes; remove from the heat.
- Raise the oven to 220°C / 200°C fan. Unroll the pastry on a lightly floured baking sheet. Score a 2cm border all the way around without cutting through. Prick the centre several times with a fork.
- Brush the centre lightly with the remaining oil. Spread the onions within the border, arrange the beetroot over them, then season with the remaining salt, pepper and thyme. Keep the border clear so it can rise.
- Bake for 18–22 minutes until the pastry is risen and deep golden underneath. If the centre puffs, press it down gently with a spoon. Scatter over the goat cheese and return to the oven for 3–4 minutes, just to soften it.
- Rest for 5 minutes, then slice with a sharp knife and serve warm or at room temperature.
Allotment tip
Roast beetroot ahead and chill it, or use plain cooked beetroot drained and patted dry. Avoid pickled beetroot: its vinegar makes the pastry wet and changes the flavour.
Cooking tips
Cook the onions low and slow while the beetroot roasts. Let both cool before topping the pastry so steam does not soften the base.
Common mistakes to avoid
Do not cut the pastry through when scoring the border. Wet or hot toppings can make the middle soggy; drain and cool the beetroot, and keep the onion mixture thick.
Serving suggestions
Serve with peppery leaves dressed with cider vinegar and olive oil, or cut into small squares for a buffet.
Seasonal allotment note
Beetroot is sown from spring to early summer for summer and autumn harvests; late-sown roots can store well. Red onions are lifted in summer and dried before storage.
Ingredient swaps
For a vegan version, choose puff pastry made with plant fat and without lard, omit the goat cheese and finish with 2 tbsp toasted walnuts or a spoonful of unsweetened plant-based feta. Check pastry and cheese labels for dietary suitability.
Allergens: Gluten (pastry) Milk (butter pastry and goat cheese)
Storing leftovers
Refrigerate leftovers in a covered container within 2 hours and eat within 48 hours. The pastry softens after chilling; reheat once on a baking tray at 180°C / 160°C fan until piping hot, or enjoy cold. The baked tart can be frozen in portions, though pastry may be less crisp after thawing.