2. In a medium bowl, whisk together milk, heavy cream, eggs, yolk, and nutmeg. Season with salt and pepper. Strain through a sieve into a medium bowl; set aside.
3. On a lightly floured surface, roll out pâte brisée to slightly less than 1/8 inch thick. Use a 2 3/4-inch round cutter to cut out 24 rounds. Fit rounds into a 24-cup nonstick mini muffin tin. If the pâte brisée becomes too soft to work with, place in refrigerator to chill for 15 minutes. Divide half of cheese evenly between the lined cups. Top with mushrooms and smoke beef. Divide milk mixture evenly between cups. Top each with smoke beef. Sprinkle with remaining cheese.
Pâte Brisée (Pie Dough)
1. In the bowl of a food processor, combine flour, salt, and sugar. Add butter, and process until the mixture resembles coarse meal, 8 to 10 seconds.
2. With machine running, add ice water in a slow, steady stream through feed tube. Pulse until dough holds together without being wet or sticky; be careful not to process more than 30 seconds. To test, squeeze a small amount together: If it is crumbly, add more ice water, 1 tablespoon at a time.
3. Divide dough into two equal balls. Flatten each ball into a disk, and wrap in plastic. Transfer to the refrigerator, and chill at least 1 hour. Dough may be stored, frozen, up to 1 month.