1 2/3 cups plain flour
170g unsalted butter, chilled, chopped, plus extra
2 tbs black chia seeds
4 eggs, plus 1 egg yolk
2 small red onions, thinly sliced
1 tbs. brown sugar
1 tbs balsamic vinegar
240g button mushrooms, chopped
230g soft goats cheese
Salt and pepper, to taste
Salad greens, to serve
Balsamic glaze, to serve
1. Place flour, 120g butter and 1/2 tsp salt in a food processor and process until mixture resembles fine crumbs. Add chia seeds, 1 egg and 1tbs iced water and pulse until mixtures comes together in a smooth ball. Shape into a disc and cover with plastic wrap. Chill in the fridge for 30 minutes.
2. Melt remaining butter in a frypan with a dash of olive oil over medium-low heat. Add onion and cook, stirring occasionally, until onion is soft. Add sugar and balsamic vinegar. Cook for a furhther 5 minutes or until onion is caramelised. Set aside to cool.
3. Heat 2tbs of olive oil in a clean frypan and add 20g of butter. Cook mushrooms until soft. Add salt and pepper to taste. Set aside to cool completely.
4. Grease a 26cm loose-bottom tart pan. Roll out pastry on a lightly floured clean surface to 3mm thick, then use to line prepared pan. Chill for 15 minutes. Preheat oven to 190 degrees Celsius.
5. Prick pastry base with a fork, then line with baking paper and fill with pastry weights or rice and bake for 10 minutes. Remove the baking paper and weights, then return to the oven for a further 6-10 minutes until the pastry is golden brown. Reduce the oven temperature to 170 degrees Celsius.
6. Place remaining eggs, egg yolk, cream and goats cheese in a clean food processor. Season with a pinch of salt and whiz until smooth. Spread onion and mushroom mixture over pastry base and top with the goats cheese and cream mixture. Return tart to the oven and bake for 25-30 minutes or until filling is just set. Cool in the pan for 10 minutes. Serve with salad greens.