In a pan set over a medium heat, fry the bacon lardons until they are golden brown and crispy.
Remove them from the pan, and set aside.
Peel and chop the onion, and fry it in the same pan until it's golden - add some oil if there is not enough fat left from the bacon.
Remove from the heat, and set aside until the quiches are ready for assembly.
Heat up the oil in the frying pan, add the butter and allow it to melt, then add the mushrooms cut into quarters and fry until golden.
Add the peeled and chopped garlic and dill, give it a good stir, and set aside.
To assemble the quiches, roll the pastry, and use a large cookie cutter or a mug/glass to cut out circles - the mug I used has a diameter of 10cm/ 4 inches.
Fit each circle onto each hole of the muffin tin - I greased and floured the tin before adding the pastry to it.
Divide the bacon and onion between 4 pastry cases, the next 4 will be filled with cheese and mushrooms, and the remaining 4 with cheese and chive.
In a jug, beat the eggs well with the salt and pepper, add the milk, and beat again.
Pour the mixture over each quiche, then bake in the preheated oven at 180 degrees Celsius (350 Fahrenheit) for 25 minutes until the pastries are golden and the fillings are set.
To remove from the tin, run a sharp knife around each quiche, then should pop out easily.
Serve either warm or cold.