Sardine and onion tart

Makes 4 tarts
1 hour 30 minutes

Ingredients

Sardine tart filling

  • 425g of whole sardines
  • 2 eggs
  • 1 egg yolk
  • 100ml of dashi
  • 125g of butter
  • 50ml of double cream

Lyonnaise onions

  • 2 brown onions, finely sliced
  • vegetable oil
  • Maldon salt

Onion ash

  • 2 brown onions, finely sliced

Tart cases

  • 3 sheets of feuille de brick pastry
  • 50g of butter, melted
  • 10g of squid ink

Method

1
Preheat an oven to 100ºC/gas mark 1/4. To make the onion ash, spread the sliced onions out on a baking tray and cook for 5–6 hours until very dark brown, dried and crispy. Blend into a fine powder and reserve until ready to assemble
  • 2 brown onions
2
Turn the oven up to 200ºC/gas mark 6 and preheat a water bath to 62°C
  • 2 brown onions, thinly sliced
  • vegetable oil
  • Maldon salt
3
Roast the sardines whole in the oven for 5-6 minutes until they're cooked through. Remove the flesh from the fish and put in a large sous vide bag along with the rest of the ingredients and seal. Cook in the water bath for 1 hour
  • 50ml of double cream
  • 425g of whole sardines
  • 2 eggs
  • 1 egg yolk
  • 100ml of dashi
  • 125g of butter
4
Meanwhile, make the Lyonnaise onions. Sweat the thinly sliced onions slowly in a pan with a splash of oil and a pinch of salt. The onions will release water as you sweat them – once this water has reduced, keep cooking the onions gently until the oil splits out and the onions are sweet and tender. Keep warm or gently reheat before serving
5
Once cooked, blend the sardine mixture until completely smooth, then pass through a fine sieve and pour into an Espuma gun. Charge with two gas canisters and reserve until ready to assemble
6
Turn the oven down to 150ºC/gas mark 2. For the tart cases, mix the squid ink with the melted butter and brush in between each layer of pastry. Cut four circles out of the layered pastry and place into 3.5cm tart cases, ensuring there is a little overhang. Bake the tart cases for about 15 minutes until crisp
  • 3 sheets of feuille de brick pastry
  • 50g of butter, melted
  • 10g of squid ink
7
To assemble, reheat the Lyonnaise onions and place in the bottom of the tart cases. Fill the remaining space with the aerated sardine filling and dust the top of the tart with the burnt onion powder to finish