1. Sauté the onion, mushrooms, garlic and thyme in the butter over a medium flame until tender, seasoning with the salt. Set aside.
2. Preheat oven to 350 degrees Fahrenheit.
3. Grease a 10-inch pie plate and sprinkle a handful of shredded cheese into the bottom of the dish. Cut each potato blintz into four slices. Lay blintzes over the cheese in the dish. Top with mushroom and onion mixture, pushing some gently between the blintz slices as well. Sprinkle remaining cheese evenly over the top.
4. In a bowl, whisk the eggs, half and half, salt and pepper. Slowly pour over all of the layered components in the pie plate.
5. Bake for 40 minutes. Remove from oven, sprinkle thyme and parmesan cheese over the top and return to oven for five more minutes.
6. Remove from oven and allow to settle 10 minutes before serving.
• May be made in advance. Freezes beautifully.
• After eating Parmesan cheese, one must wait six hours before eating meat. See more on this, including a list of all hard cheeses that require waiting, here.