Preheat the oven to 375°F (190°C).
Melt the butter in an oven-safe skillet or Dutch oven over medium heat.
Add the orzo, minced garlic, dried basil, and a big pinch of kosher salt and black pepper; cook, stirring often, for 2–3 minutes to toast the orzo slightly.
Pour in 1 1/2 cups of the stock and the marinara sauce; stir to combine.
Transfer the uncovered skillet to the preheated oven and bake for 12–15 minutes, until most of the liquid is absorbed.
Carefully remove the skillet and stir the orzo, then add the remaining 1/2 cup stock and 1 cup of the grated cheese; stir to combine.
Sprinkle the remaining grated cheese evenly over the top and return the skillet to the oven; bake for 10 more minutes, until cheese is melted and bubbly.
Remove from the oven and top with grated Parmesan, fresh basil, and crushed red pepper to taste; serve hot.
