For the puff pastry:

1. Pre-heat your oven to 400 degrees, middle rack in place. Thaw puff pastry according to manufacturer’s directions. Flour surface and roll into larger rectangle. Depending on if you’re using a jumbo-muffin tin or regular muffin tin, cut dough into 6 or 12 squares. Roll each square out large enough to fit inside each tin, with enough dough to hang along the sides. Work quickly, as puffy pastry can melt if your hands or environment is too warm. Pop it back in the fridge to keep it cold if you need to. Spray each muffin tin with non-stick cooking spray, then wipe most of it out with a paper towel. There is enough butter in puffy pastry to keep it from sticking, BUT we’d rather be safe than sorry. So wipe most of the non-stick spray off, keeping a very thin film of it in each tin. GENTLY press each square into a tin, making sure it’s sitting at the bottom and along the sides. Be careful not to tear it. if you tear it, “glue” it back together with a wet finger and immediately pop it back in the fridge to harden. Continue until each square is in the tin, then place in the freezer while you cook everything else.

For the leek, sausage, and mushroom filling:

1. Heat one tablespoon of olive oil in a medium skillet over medium-high heat. Add the sausage, and break into bite-sized chunks with a wooden spoon. Add the red pepper flake, balsamic vinegar, and cook until meat is no longer pink and balsamic vinegar is soaked into the sausage, about 4-6 minutes. Add the garlic, if using, and cook for just 30 seconds. Remove the sausage and garlic with a slotted spoon into a separate bowl, leaving behind the oil and rendered fat.
2. Reduce heat to medium, add the leeks in an even layer and cook for 1 minute without stirring. Using the wooden spoon, stir the leeks around to pick up any browned bits stuck on the bottom of the pan from the sausage. Add salt and pepper and cook the leeks down until they’re soft and translucent, about 4 to 5 minutes. Remove leeks with a slotted spoon into the bowl with the sausage.
3. If needed, add 1 more tablespoon of olive oil to the hot pan, and add the mushrooms without stirring for 1 minute. Stir the mushrooms around to help them cook down just a bit and develop some great color, about 3-5 minutes. Add the fresh herbs and cook for just 30 seconds to let their flavors bloom. Remove the mushrooms and herbs with a slotted spoon into the same bowl with the sausage and leeks. Gently mix mixture together so it’s evenly combined, then let cool in the fridge for about 10-15 minutes.

For the egg mixture:

1. In a medium-sized bowl, whisk together the eggs, cream (or milk or half & half), pinch of sea salt and black pepper, parsley, and frozen diced butter until evenly combined. Do not over-mix the eggs or they’ll come out rubbery. Finally, add the cheese and gently fold with the whisk. Set aside.

To assemble and bake:

1. Once the leek, sausage and mushroom mixture is cool, take the prepared puff pastry out of the freezer. Evenly fill each cup with the mushroom mixture, then evenly pour in the egg & cheese mixture. Using a pastry brush, paint the edges of each pastry with a little of the egg mixture inside of each pastry.
2. Immediately place inside of your hot oven and bake for 10-15 minutes, depending on the size of your muffin tin. Keep in mind, I used a jumbo-muffin tin and mine were done in exactly 15 minutes. If you’re using smaller muffin tins, your baking time will probably be reduced by a few minutes. Keep an eye on it. Edges should be golden brown and eggs should be set with a very slight jiggle. Use your best judgement. When done, remove from oven and let cool inside the tins for 10 minutes before removing. Use a paring knife to help loosen the sides if necessary, gently use your fingers to turn each pastry to ensure it’s not sticking, then pop them out and eat them. Enjoy!