• Preheat oven to 350°F. Spray a 9x13-inch casserole dish (or use seasoned cast iron) with nonstick spray.

If Using Fresh Hatch Green Chiles

• Blister and lightly char the skins by grilling, broiling, or roasting.
• Place the warm peppers in a bag or a covered bowl and steam for 20 minutes, until cool enough to handle.
• Peel off the skins, remove the stems, and take out the seeds.
• Try to keep the peppers whole so they layer neatly in the casserole

Egg Mixture

• In a large bowl, whisk together milk, eggs, flour, salt, pepper, and oregano until smooth.
• Grate the cheese(s).

Assemble the Casserole

• Add a layer of prepared Hatch green chiles to the casserole dish.
• Sprinkle with about one-third of the grated cheese.
• Repeat with another layer of chiles, then cheese.
• Pour the egg mixture evenly over the top.
• Top with the remaining cheese.
• Let the casserole stand for 10 minutes for the layers to settle.

Bake the Casserole

• Bake uncovered for 30–40 minutes (on the center rack for even cooking), or until the eggs are set and the top is golden brown.
• Tent the casserole loosely with foil if the top is browning too quickly.
• Once out of the oven, let the casserole rest 5–10 minutes before slicing for the cleanest cuts.
• Add desired toppings and garnishes for serving!