Bring a large pot of well-salted water to a rolling boil. The water should taste like the sea — this is your only chance to season the pasta from within. When the water bubbles vigorously and steam billows up, add your pasta and cook according to package directions until al dente. You'll know it's ready when it offers slight resistance to the bite but isn't chalky white inside.

While the pasta boils, heat a large frying pan over medium-high heat. Add the olive oil and wait until it shimmers — that thin, glassy sheen means it's hot enough. Toss in the diced courgettes and cook for 3–4 minutes, stirring occasionally. They should turn golden at the edges and soften slightly, releasing a faint, nutty aroma.

Add the cherry tomatoes to the pan with the courgettes. Cook for another 2 minutes until the tomatoes begin to blister and their skins wrinkle. You'll hear a soft sizzle as they hit the hot oil, and the pan will smell sweet and tangy. Sprinkle in the minced garlic and stir for 30 seconds until fragrant — don't let it burn, or it will taste bitter.

Reserve about a cup of pasta cooking water before draining. This starchy, cloudy liquid is liquid gold — it helps the pesto cling to every strand of pasta. Drain the pasta in a colander, shaking off the excess water. You'll see steam rising as the water evaporates.

Return the drained pasta to the pot (off the heat) and add the cooked vegetables. Spoon in the pesto and toss everything together using tongs or a pasta fork. The pesto will coat the pasta in a vibrant green sheen, and the aroma of basil and garlic will fill your kitchen. If the mixture looks dry, add a splash of the reserved pasta water — about 2–3 tablespoons — and toss again until glossy and creamy.

Fold in the grated Parmesan and toasted pine nuts. Stir gently until the cheese melts into the warm pasta, creating a silky, cohesive sauce. Taste and adjust seasoning with salt and pepper — remember, the Parmesan and pesto are already salty. Squeeze over the lemon juice if using, and garnish with torn basil leaves. Serve immediately while the pasta is still steaming and the vegetables are tender.