Prepare the Pasta Water: Bring a large pot of water to a rolling boil. Salt it generously – it should taste like the sea. This is your only chance to season the pasta itself.

Cook the Pasta and Broccoli: Add the pasta to the boiling water and give it a good stir. Check the packet instructions for the cooking time. About 4-5 minutes before the pasta is due to be al dente, add the broccoli florets to the same pot. This allows them to become perfectly tender without turning to mush.

Start the Sauce: While the pasta and broccoli are cooking, heat the extra virgin olive oil in a large frying pan or skillet over a medium-low heat. Add the sliced garlic (and the optional chilli flakes). Cook gently for 2-3 minutes, swirling the pan, until the garlic is fragrant and just beginning to turn a pale gold. Be very careful not to let it brown or it will become bitter. I find that keeping the heat low is crucial here.

Combine and Create the Sauce: Just before draining the pasta and broccoli, use a heatproof mug to reserve about 300ml of the starchy cooking water. Drain the pasta and broccoli well in a colander.

Bring It All Together: Tip the drained pasta and broccoli into the frying pan with the garlic oil. Turn the heat up to medium. Add about half of the reserved pasta water, the grated Parmesan, and the lemon zest. Use tongs to toss everything together vigorously for 1-2 minutes.

Emulsify: This is the most important step! As you toss, the starchy water, oil, and cheese will come together to form a creamy, glossy sauce that coats every single piece. This process is known as emulsification and it's what gives the dish its luxurious texture. If the sauce looks a little thick, add another splash of pasta water until it reaches your desired consistency.

Finishing Touches: Take the pan off the heat. Stir in the fresh lemon juice and season generously with black pepper and a little more salt if needed. Serve immediately in warm bowls, with an extra grating of Parmesan on top.