Preheat your oven to 200°C (390°F). Place the whole red peppers on a baking tray and roast for 25–30 minutes, turning once halfway, until the skin is charred and blistered all over. Remove from the oven, place in a bowl and cover for 10 minutes — the steam loosens the skin beautifully. Peel, deseed, and slice into strips.
Bring a large pot of water to a boil. Cook the pasta according to package instructions until al dente. Reserve a small cup of pasta cooking water before draining — this starchy water is liquid gold for bringing the sauce together later.
Heat the olive oil in a large skillet over medium-low heat. Add the sliced garlic and cook gently for 2–3 minutes until soft and lightly golden — watch it carefully, burnt garlic will ruin the dish. Add the sardines and break them up gently with a fork into chunky pieces. Add the roasted pepper strips and stir everything together for 2 minutes.
Add the drained pasta directly to the skillet. Toss everything together well, adding a splash of reserved pasta water to loosen the sauce if needed. Squeeze in the lemon juice, add the black pepper and chilli flakes if using, and toss again. The pasta should be glossy and well coated.
Divide between two bowls and scatter fresh parsley generously over the top. Finish with a final drizzle of extra virgin olive oil over each bowl. Serve immediately.