Prepare the courgette noodles: Using a spiraliser or julienne peeler, turn your courgettes into long, thin noodles. You'll know they're ready when you have a large bowl of springy, pale green strands that look like thick spaghetti. Pat them dry gently with a clean tea towel to remove excess moisture — this is crucial for avoiding a watery dish later.

Season and cook the prawns: Pat the prawns dry with kitchen paper and season generously with salt and pepper. Heat half the olive oil in a large frying pan over medium-high heat until it shimmers and you can smell the oil warming. Add the prawns in a single layer — you should hear a satisfying sizzle. Cook for 2 minutes on each side until they turn from translucent grey to a bright, opaque pink with golden-brown edges. Transfer them to a plate and set aside.

Build the garlic butter base: Reduce the heat to medium and add the remaining olive oil and the butter. Once the butter has melted and is gently bubbling, add the minced garlic. Stir constantly for about 30-40 seconds until you can smell that unmistakable, fragrant garlic aroma. Be careful not to let it turn brown, as burnt garlic tastes bitter.

Cook the zucchini noodles: Add the courgette noodles to the pan in handfuls, using tongs to toss them gently. Cook for just 2-3 minutes — you want them to soften slightly but still hold their shape. You'll notice they become more pliable and start releasing a little steam, but they should not be swimming in liquid. The texture should be al dente, with a slight resistance when bitten.

Add the prawns and finish the sauce: Return the cooked prawns to the pan, along with the lemon zest, lemon juice, and chilli flakes if using. Toss everything together for about 30 seconds until the prawns are heated through. Pour in the cornflour slurry and stir — you'll see the thin liquid at the bottom of the pan thicken into a glossy, light sauce that clings to the noodles and prawns.

Season and serve: Remove from the heat, taste, and adjust seasoning with salt and pepper. Sprinkle over the chopped parsley and Parmesan cheese if using. The finished dish should look vibrant: pink prawns against pale green noodles, flecked with green parsley and a glossy sheen from the sauce.