Preheat an outdoor grill for high heat, and coat a grill basket with cooking spray.
Mix bread crumbs, almonds, chopped thyme, and black pepper together in a shallow dish.
Dip each trout fillet in milk, then dredge each in the bread crumb mixture. Coat each fillet with cooking spray.
Place dredged fillets in prepared grill basket and cook until golden and fish flakes easily with a fork, about 5 minutes on each side. Garnish with thyme sprigs.
To pan-fry the fillets instead of grilling, heat 2/3 cup olive oil in a large skillet over medium high heat. Carefully place fillets in the oil and cook until golden, about 3 minutes per side. Remove from skillet and place on paper towels to drain excess oil.