Position a rack in the upper third of the oven; preheat to 400 degrees . Line a baking sheet with foil; coat with cooking spray.
Using a food processor, pulse 2 cups arugula, 1 cup EVOO, 1/2 cup each walnuts and parmesan, and pinch salt.
Combine the breadcrumbs, meatloaf mix, garlic, egg, 1 tsp. salt and 1/2 tsp. pepper. Shape into a 5-by-8-inch rectangle on the sheet.
Bake until a thermometer inserted in the center registers 160 degrees , 40 minutes. Let rest for 10 minutes before slicing.
