Once the mushrooms are nice and brown, move them over to one side of the skillet and add the butter. Once the butter melts, add the garlic and flour, and cook a minute or so. Add the balsamic, allowing it to slightly reduce, then the chicken stock. Cook everything down until thick and creamy.
While the gravy is thickening up, place the dried mushrooms, breadcrumbs, cheese, salt and freshly ground pepper in a food processor and pulse until the mushrooms have are powder-like. Place the mushroom-breadcrumb mixture into a large, shallow dish.
Set up two more shallow dishes: In one dish, combine 1 1/2 cups flour and poultry seasoning. In the other, whisk up the eggs and milk. Dip the cutlets into the seasoned flour, then into the egg mixture, then into the cheesy mushroom-breadcrumb mixture. Repeat with the rest of the turkey cutlets.
Heat a large skillet with 2 tablespoons of EVOO over medium-high heat. Cooking in batches to avoid crowding the pan, add the breaded cutlets and cook for about 3-4 minutes on each side, until nice and golden brown on each side. When the first batch is done cooking, place them in the oven to keep them warm and crispy.
While the cutlets are cooking, get another skillet over high heat with a tablespoon of EVOO. Add the spinach to the skillet, cook until slightly wilted down -- not too much; you still want to have a little crunch to the spinach. Season with salt, pepper and nutmeg.
Remove the turkey cutlets from the oven and serve them up with the creamy mushroom-balsamic gravy on top and the wilted spinach alongside.