Bring a large pot of salted water to a rolling boil and add your pasta. Cook according to package directions until al dente, usually about eight to ten minutes. Before draining, save one cup of the starchy pasta water—this liquid gold helps create a silky sauce later.

While the pasta cooks, heat olive oil in a large skillet over medium heat. Add finely diced onion and sauté until soft and translucent, about four minutes. The kitchen will start smelling absolutely wonderful at this point.

Toss in minced garlic and cook for just one minute, stirring constantly so it doesn't burn. You want it fragrant and golden, not bitter.

Pour in the heavy cream and bring it to a gentle simmer. Let it bubble softly for two to three minutes until it thickens slightly. Season with salt, pepper, and a pinch of red pepper flakes for a subtle warmth.

Drain your canned tuna and flake it gently with a fork. Add it to the cream sauce along with the peas if you're using them. Stir everything together and let it warm through for about two minutes.

Add the drained pasta directly to the skillet with the creamy tuna sauce. Toss everything together, adding splashes of reserved pasta water as needed to achieve your desired consistency. The sauce should cling lovingly to every piece of pasta without being too thick or too thin.

Remove from heat and stir in freshly grated Parmesan cheese. Taste and adjust seasonings as needed. Sometimes I add an extra squeeze of lemon juice here for brightness, though it's completely optional.