Prepare mise en place: measure ingredients, zest and juice the lemon, mince the garlic, crumble the sausage, and rinse the spinach. Getting everything organized shortens cooking time and ensures nothing is overcooked — gnocchi and spinach both cook fast.

Bring a large pot of well-salted water to a rolling boil. Salted water seasons the gnocchi from the inside as it cooks; use about 1 tbsp salt per 4–5 L of water (it should taste like the sea). Keep the pot boiling and ready.

Char the sausage to deepen flavor: heat a large skillet or cast-iron pan over medium-high heat until hot. Add 1 tsp of the olive oil and add the crumbled sausage in a single layer. Let it sit without stirring for 1–2 minutes to get contact browning, then break up and continue browning until well caramelized, about 6–8 minutes total. Browning creates Maillard flavors that will make the ragù savory and complex.

Add garlic and deglaze: push the browned sausage to one side, lower heat to medium, add the remaining olive oil and the minced garlic. Cook 30–45 seconds until fragrant — do not let it burn. If bits are stuck to the pan, use 1–2 tbsp of hot pasta water (reserved from the pot) to deglaze and lift those browned fond into the ragù for extra flavor.

Simmer briefly to meld: once garlic is aromatic, stir everything together and let the ragù cook gently for 2–3 minutes so the flavors marry. Turn the heat to low and keep warm while you cook the gnocchi. This short simmer keeps the sausage juicy rather than drying it out.

Cook the gnocchi: add the gnocchi to the boiling water and cook according to package directions (fresh gnocchi typically rise to the surface in 1–3 minutes; dry may take a minute or two longer). Do not overcook — gnocchi should be tender and pillowy, not gummy. When they float, scoop them out with a slotted spoon into a bowl and reserve about 1/2 cup (120 ml) of the starchy cooking water.

Make the lemon-ricotta emulsion: in a large serving skillet or bowl, combine ricotta, lemon zest, lemon juice, and 2–3 tablespoons of reserved hot gnocchi water. Whisk or stir vigorously to create a glossy, slightly loose emulsion that will coat the gnocchi. The hot water loosens the ricotta so it becomes silky instead of clumping.

Wilt the spinach: add the spinach to the warm ragù pan (or a separate skillet if preferred) and toss for 30–60 seconds until just wilted. Spinach wilts quickly — gentle heat keeps it bright and tender, preserving color and nutrients. Season lightly with salt and pepper.

Combine gnocchi, ricotta emulsion and spinach: add the drained gnocchi to the lemon-ricotta emulsion, then gently fold in the wilted spinach and the sausage ragù. If the sauce is too tight, add more reserved pasta water a tablespoon at a time until the sauce clings to the gnocchi. Finish with the butter, if using, stirred in for sheen and extra richness.

Check seasoning and finish: taste and season with salt and plenty of freshly ground black pepper. Swirl in the remaining 1 tsp lemon zest (for fragrance) and 1 tsp lemon juice if you want a livelier citrus pop. The final lemon brightens the fat-rich components and lifts the whole dish.

Plate and garnish: divide between warmed plates or shallow bowls, drizzle a little extra virgin or basil oil over each portion, and finish with a sprinkle of grated Parmigiano-Reggiano if using. Serve immediately so the gnocchi remain pillowy and the ragù stays warm.