Heat 2 tablespoons of olive oil in a large skillet over medium-high heat until the oil shimmers. Working in batches — do not crowd the pan, as this causes steaming rather than browning — add the meatballs and cook for 2 to 3 minutes on each side until a deep golden-brown crust forms on the exterior. They will not be cooked all the way through at this stage, which is intentional — they will finish cooking in the sauce. After browning each batch, transfer the meatballs to a plate and continue with the remaining ones, adding a small amount of additional oil if needed between batches.
Step 6: Simmer Meatballs in the Sauce
Gently lower the browned meatballs into the simmering tomato sauce, nestling them carefully so they are partially submerged. The sauce should be at a gentle, steady simmer — not a rolling boil, which would make the meatballs tough. Cover the pot partially with a lid, leaving a small gap for steam to escape, and simmer for 25 to 35 minutes, turning the meatballs once or twice very gently during this time. As they cook, the meatballs will absorb flavor from the sauce while simultaneously enriching it with their meaty juices. The sauce will thicken and deepen in color. The meatballs are done when they are cooked through to an internal temperature of 165°F (74°C) and feel firm but yielding when gently pressed.
Step 7: Taste and Adjust
Once the meatballs are cooked through, taste the sauce and adjust the seasoning with additional salt, pepper, and sugar as needed. If fresh basil is available, tear a few leaves and stir them into the sauce at this point — the heat of the sauce will release their fragrance without making them bitter. The finished sauce should be rich, slightly thick, and deeply savory with a balanced tomato flavor that is neither too acidic nor too sweet.
