Adjust the oven rack to the middle position and preheat the oven to 375°F.
Fill a medium bowl halfway with water and put about a dozen ice cubes in it. Set it aside.
Bring 4 quarts water to a boil in a large pot. Add 1 tablespoon salt and blanch the spinach in the boiling water until it's bright green, about 40 seconds. Immediately strain it, place it in the ice water, and let it cool for 2 minutes (the ice water will stop the spinach from overcooking and help it retain its color). Squeeze the spinach dry with a kitchen towel.
Combine the parsley, chives, scallions, and shallots in a small bowl. Open each fish like a book, season the cavity generously with salt and pepper, and sprinkle with the herb mixture. Stuff the trout with the blanched spinach, and close the fish back up.
To create a prosciutto wrapper for each trout, take 4 slices prosciutto and arrange them into a large rectangle, with the edges overlapping by 1/2 inch to help keep the pieces together. You should end up with what looks like a rectangular patchwork quilt of ham. Take one of the stuffed fish and wrap it in the prosciutto as if you were rolling it tightly in a piece of newspaper. When you're finished, the fish should be entirely wrapped in prosciutto. Smooth down the loose ends of prosciutto with your fingers to seal it. Repeat this process with each fish.
Heat a cast-iron skillet over medium-high heat, drizzle 2 tablespoons of the oil into it, and add 1 tablespoon of the butter. Put 2 fish in the skillet and cook until the prosciutto is crisp, about 4 minutes. Flip the fish over and cook until the prosciutto on the other side is crisp as well, another 4 minutes. Transfer the trout to a baking sheet lined with aluminum foil. Wipe the skillet clean with paper towels and repeat with the remaining fish, using the remaining 2 tablespoons oil and 1 tablespoon butter.
When all the fish are ready, place the baking sheet in the oven and bake for 8 to 10 minutes, until the flesh of the trout has turned opaque. Let them rest for 2 minutes. Then carefully transfer the baked trout to a cutting board, and using a sharp knife, halve each fish crosswise so that your guests can appreciate the trout's pinkish color and its spinach center. Arrange the trout on a platter, drizzle with the Meyer lemon dressing, and serve.
Serves: 4
Reprinted with permission from ©Big Sur Bakery, LLC, The Big Sur Bakery Cookbook, by Michelle & Philip Wojtowicz and Michael Gilson with Catherine Price, Published by William Morrow click for book review
NOTE: " Salmon trout is a pink-fleshed fish, abundant in the lakes and rivers of Idaho. If you have difficulty finding salmon trout, you can use rainbow or brown trout instead."