A simple nut crust takes trout to the next level. Using a hand blender fitted with a mini food chopper, like the Braun MultiQuick 9, you can quick crush whole nuts and herbs for the crust. —Samantha Weiss Hills
Make the walnut crumble. Add walnuts, rosemary, thyme, garlic, and Pecorino to a food processor or chopper and pulse a few times. You don't want to process it so much that it becomes smooth; it should all be a uniform crumble. Add salt and pepper to taste. Set aside.
Season trout with salt and pepper. Crack the egg into a wide, low pan or dish and mix with a fork. Working one at a time, dip skin side of fillets into egg, then in walnut crumble, pressing to adhere. Transfer to a plate as you go.
Heat oil in a large skillet over medium-high until very hot but not smoking. Cook 1 fillet, walnut side down, pressing with a spatula occasionally to ensure contact with skillet, until the nut crumble is well toasted and fish is nearly cooked through, about 3 minutes. Turn and cook until opaque throughout, about 1 minute more. Transfer to a plate. Repeat with remaining fillet.
Note: If you're having trouble handling the fish at the 10-ounce size, feel free to cut it in half before applying the egg wash. It is sometimes easier to add it to the pan without all your crumble falling off that way.
Serve immediately with garlicky sautéed greens or a fresh salad, and maybe your favorite roasted potatoes.