Combine soy sauce, lemon juice, mirin, 2 tablespoons water and bonito in small bowl. Let stand 30 minutes. Strain sauce through fine strainer; discard bonito shavings. (Can be made 4 hours ahead. Cover and let stand at room temperature.)
An ex-boyfriend’s mom—who emigrated from Colombia—made the best meat sauce—she would fry sofrito for the base and simply add cooked ground beef, sazón, and jarred tomato sauce. My version is a bit more bougie—it calls for caramelized tomato paste and white wine—but the result is just as good.