For the crust, take all-purpose flour in a large bowl. Add in salt and chilled butter cut into small pieces. Rub in the butter to get a breadcrumb texture. Add in a little chilled water, just enough to knead the dough. Cover the dough and refrigerate for at least half an hour. For the filling, heat 1 tbsp of olive oil in a pan. Add in finely sliced onions and cook until translucent. Add in ginger garlic paste and saute for a minute. Add in the finely sliced chicken and cook for a few minutes.
Next, add in the sliced mushrooms with a teaspoon of salt. Mix well. Cover it with a lid and cook until the juices dry up.
Preheat the oven at 180°C. Grease the pie dish well. Roll out the dough. It should not be too thick or too thin.
Place the rolled-out dough over the pie dish. Press the dough into the pan and the sides with your fingers. Remove the extra dough with a knife.
Prick it with a fork so that it does not rise. To blind bake, place the parchment paper on top and fill it with baking weights. Bake it at 180°C for 15-20 minutes until the sides are lightly colored.
Remove the parchment paper with the weights. Bake again at 180°C for 5 minutes.
In the meantime, prepare the custard. In a large bowl, whisk together eggs, cream, mustard paste, Worcestershire sauce, all-purpose flour, cornflour, and baking powder. Keep aside.
To assemble, add the filling into the crust. Make sure you do not de-mould the crust from the pie tin. Top it with a few basil leaves.
Add in a cup of grated cheese.
Pour in the custard. Make sure it seeps in well.
Garnish with sliced cherry tomatoes and a few more basil leaves.
Bake the quiche in a pre-heated oven at 180°C for 20-25 minutes or until done. Check with a skewer or a knife. It should come out clean.
Once cooked, remove from the oven and let it stand for a few minutes before you de-mould.
The Chicken Mushroom Quiche is ready to serve.