Prep ingredients: finely dice the onion, mince the garlic, chop the basil/parsley, and measure out the breadcrumbs and Parmesan. Prepping everything first keeps the work flowing and ensures you don't overcook aromatics while searching for ingredients.

Hydrate the breadcrumbs: put 40 g (about 1/3 cup) whole-wheat breadcrumbs in a small bowl and stir in 2 tbsp milk (or water). Let sit 3–5 minutes until the crumbs absorb the liquid. Hydrated crumbs keep the meatballs tender without adding extra fat.

Mix meatball base: in a large bowl combine 660 g ground turkey, the hydrated breadcrumbs, 1 large egg, 2 tsp Italian seasoning, 1 tsp freshly ground black pepper, 1 tsp of salt (reserve the remaining 1/2 tsp for the sauce), half the grated Parmesan (2 tbsp), and the minced garlic. Use your hands or a fork to gently but thoroughly combine; overworking the meat compacts it and makes dense meatballs, so stop as soon as the mixture is cohesive.

Form even meatballs: wet your hands with a little water to prevent sticking and shape the mixture into 16 meatballs (~40–45 g each / about 1.5 oz). Uniform size ensures even cooking and a better presentation.

Brown the meatballs: heat 1½ tbsp olive oil in a large heavy skillet over medium-high heat. When the oil shimmers, add meatballs without crowding—work in 2 batches if needed. Sear for 2–3 minutes per side until a deep golden crust forms, turning gently. Browning creates Maillard flavor and helps the meatballs hold together when simmered.

Sauté aromatics: remove browned meatballs to a plate. Add the remaining ½ tbsp olive oil to the skillet (if it looks dry), reduce heat to medium, then add the diced onion. Sauté 4–5 minutes until translucent and starting to caramelize—this sweetness balances the tomato acidity. Add the minced garlic and 1/4 tsp red pepper flakes (if using) and cook 30–45 seconds to bloom the garlic’s aroma—don’t let it brown or it will turn bitter.

Build the sauce: pour the 28 oz (794 g) crushed tomatoes into the skillet with the onions, scrape any browned bits from the pan (those are concentrated flavor). Stir in remaining 1/2 tsp salt and the remaining 2 tbsp grated Parmesan. Bring the sauce to a gentle simmer to meld flavors; simmering for 8–12 minutes reduces raw tomato flavor and thickens the sauce just enough to cling to the meatballs and pasta.

Simmer the meatballs in sauce: nestle the seared meatballs into the simmering sauce, spooning sauce over each one so they’re partially submerged. Cover and simmer gently for 10–12 minutes, or until an instant-read thermometer inserted into the center reads 74°C (165°F). Simmering in sauce finishes cooking while keeping the meatballs moist and infusing them with tomato flavor.

Cook the pasta: while the meatballs simmer, bring a large pot of salted water to a rolling boil (1 tbsp salt per 4–5 liters water). Add 340 g dry whole-wheat spaghetti and cook according to package directions until al dente (usually 8–10 minutes). Reserve 1 cup (240 ml) of pasta cooking water before draining—the starchy water helps emulsify the sauce and pasta later.

Finish sauce and assemble: if sauce is too thick, stir in 2–4 tbsp reserved pasta water to loosen it. Taste and adjust seasoning with remaining salt and pepper. Add half of the chopped basil/parsley to the sauce. Toss drained spaghetti with a few ladlefuls of sauce in a large warm bowl or skillet so each strand gets sauced—this prevents piling plain pasta under the meatballs and helps the pasta absorb flavor.

Plate: divide sauced spaghetti among 4 plates (about 1.5 cups cooked per serving), top with 4 meatballs each, spoon extra sauce over, and finish with the remaining Parmesan and fresh basil or parsley. A sprinkle of extra-virgin olive oil immediately before serving adds shine and mouthfeel.

Serve: present immediately while hot. Leftovers keep well refrigerated for 2–3 days; reheat gently in a skillet with a splash of water to rehydrate the sauce.