Pour the fish stock into a 3-quart / 2.8 L saucepan and bring to a bare simmer over low heat. Keep it warm on the back burner while you cook.
Heat the olive oil in a 30 cm / 12-inch risotto pot over medium heat. Add the onion and garlic and cook 4 to 5 minutes, stirring, until soft and translucent.
Add the cuttlefish strips and cook 3 to 4 minutes, stirring, until just opaque. Season with a pinch of salt.
Add the rice and stir constantly for 2 minutes, until the edges of the grains look glassy.
Pour in the white wine and stir until it's fully absorbed, about 1 to 2 minutes.
Add a ladle of hot stock, stirring until absorbed before adding the next. Repeat this for about 8 minutes.
Once the pot is hot and steady, stir the squid ink into the next ladle of stock before adding it, mixing until the rice turns evenly black.
Keep adding stock one ladle at a time, stirring often, for another 8 to 10 minutes, until the rice is al dente and the mixture is loose enough to spread slowly across the plate when you tilt it.
Remove the pot from the heat. Stir in the cold butter and parsley until glossy, then cover and rest 1 minute.
Spoon onto warm plates and serve with lemon wedges and a crack of black pepper.