For the Pasta: Bring a large pot of salted water to a boil. Cook pasta until al dente, following timing on package's instructions. Reserve ½ cup pasta water, then drain.
While water comes to a boil, in a large skillet, combine oil and garlic and cook over medium-low heat, stirring occasionally, until garlic is soft, fragrant, and just turning pale golden, 5 to 7 minutes. Add gochujang and cook, stirring frequently, until it loosens and darkens slightly, about 1 minute.
Stir in passata and salt. Bring a simmer and cook over medium-low heat until flavors meld and sauce slightly thickens, 8 to 10 minutes; lower heat as needed if sauce begins to bubble aggressively. Remove from heat until bucatini is ready.
Return tomato-gochujang sauce to a gentle simmer over medium-low heat. Add drained bucatini and ½ cup reserved pasta water. Stir until well-combined and sauce clings to the bucatini, about 1 minute. Season with salt to taste, if needed.
To Serve: Transfer pasta to serving bowls, top with a dollop of ricotta, black pepper, and basil leaves.
