How to Make It
In a medium skillet, heat the olive oil until shimmering. Add the onion, garlic and a generous pinch each of salt and pepper and cook over moderate heat, stirring occasionally, until the onion is softened, about 7 minutes. Scrape the onion mixture into a large bowl. Using a rubber spatula, fold in the 1/4 cup of parsley and the basil. Let cool to room temperature, about 20 minutes.
Preheat the oven to 375°. Add the ground turkey, turkey sausage, crushed crackers, cheese, mayonnaise, eggs, oregano, crushed red pepper flakes, 2 teaspoons of salt and 1/2 teaspoon of black pepper to the cooled onion mixture. Using your hands, mix gently until combined.
Transfer the meat mixture to a parchment paper–lined baking sheet and pat it into a 5-by-11-inch loaf. Bake for about 40 minutes, until the meat loaf is browned and an instant-read thermometer inserted in the center registers 165°. Remove the meat loaf from the oven and spoon the marinara sauce on top.
Turn on the broiler and broil the meat loaf until the marinara sauce is browned in spots, 3 to 4 minutes. Let the meat loaf stand for 15 minutes, garnish with chopped parsley and serve.