Preheat your oven to 400 degrees F and line a large baking sheet with parchment paper.
In a small bowl, combine the gluten free breadcrumbs and milk. Let them soak for about 5 minutes until the breadcrumbs are soft and have absorbed the liquid.
In a large bowl, combine the ground beef, ground pork, soaked breadcrumbs, egg, minced garlic, parsley, parmesan, salt, and pepper. Mix gently with your hands until just combined, being careful not to overwork the meat.
Roll the mixture into about 20 meatballs, roughly 1 1/2 inches each, and place them on the prepared baking sheet. Bake for 18 to 20 minutes until golden brown and cooked through.
While the meatballs bake, bring a large pot of salted water to a boil. Cook the gluten free spaghetti according to package directions until al dente, then drain.
Heat the marinara sauce in a large deep skillet or pot over medium heat. Once the meatballs are done, add them to the sauce and gently simmer together for 5 minutes so the flavors meld.
Toss the drained spaghetti with a drizzle of olive oil and divide among serving plates. Spoon the meatballs and sauce over the pasta and top with fresh basil and grated parmesan.