If you have not, remove your shortcrust pastry and set it in a sunny spot to allow it to fully defrost
In a small ramekin, combine all your spices, including your baking powder, and stir well.
On medium heat, heat your pan along with your vegetable oil. Once your oil is hot, add your finely chopped onion, yellow pepper and mushrooms. Stir continuously for about 5 minutes.
Whilst continuously stirring your vegetables, add your spices to them then mix well.
Set your vegetables aside.
Preheat your oven for 180 degrees Celsius on bake.
In a large mixing bowl, crack your eggs into it. Add milk and the grated cheese to the bowl and whisk well. Set your egg mixture aside.
Grease your cupcake pan with butter, make sure you do this part carefully for this will prevent your quiche from burning.
Roll out your store-bought pastry and cut it into equal square parts. Make sure that the squares are big enough to fit into the cupcake holder.
Place each piece of pastry into each cupcake hole, make sure to use two fingers to push the pastry down into the edges.
Once this is done, add a tablespoon of filling into each quiche. Then add your egg mixture into each mini quiche. Make sure you do not fill the egg mixture to the top of the cupcake holder, this will prevent your quiche from spilling and burning.
Use your fork to gently mix the filling, then bake your quiche for 25 -35 minutes.
Remove your quiche from the oven and enjoy.