Try this Bacon Mushroom Mini Quiches recipe, or contribute your own.
Achieving a shatteringly crisp exterior relies entirely on how the filo sheets are handled. Spraying each individual layer with oil creates micro-barriers of fat between the sheets. As the oven heats the water content in the pastry, steam forces those layers apart, generating flaky separation rather than a dense, soggy shell. Pressing the stacked squares firmly into the greased patty tins ensures the pastry holds its structural integrity against the liquid filling.
Button mushrooms release substantial water when heated. Sautéing the chopped mushrooms until they turn thoroughly golden and soft evaporates excess moisture. Trapped liquid will bleed into the surrounding egg mixture during baking, preventing the custard from setting properly. Cook the bacon and onion first until rendered, then add the fungi to a dry frying pan to encourage browning.
Bake the filled tins at 180C, or 160C for fan-forced ovens, for 30 to 35 minutes. Piercing the center is unnecessary when visual cues are clear. Watch for the cheese topping to turn deep amber and bubble actively. The pastry edges must appear rigid and deeply golden before extraction from the heat source.