3 tablespoons unsalted butter (broken into several pieces)
1 pound short pasta (cooked to al dente and drained, 1/4 cup of the cooking water reserved)
Freshly ground black pepper to taste
Steps
In a skillet large enough to hold the pasta, heat the oil, 1 1/2 teaspoons of the garlic, the red chile pepper flakes, and capers over medium heat until fragrant (but not browned), about 1 minute.
Add the wine and bring to barely a simmer; cook for 1 minute.
Add the tuna and salt to taste and sauté over low heat for 1 minute.
Toss the tuna-caper mixture with the remaining 1 1/2 teaspoons of minced garlic, the parsley, lemon zest, butter, cooked pasta, and as much of the reserved pasta cooking water as needed to form a creamy sauce that coats the pasta. Season with freshly ground black pepper and serve immediately.