Bring a large pot of salted water to a boil. Add the pasta and cook according to instructions on the packet, reducing cooking time by 1 minute.
water to boil pasta, 1 teaspoon salt, 8 ounces penne
In the meantime, on a medium flame, heat the oil with the chilli and garlic in a large skillet. As the garlic begins to turn golden, add the tomato paste and stir. Add salt and pepper, then add the shrimps. Cook for 3-4 minutes, till the shrimps are heated through.
1 teaspoon salt, 1 tablespoon olive oil, 2 cloves garlic, minced, a pinch chilli flakes, 75 grams tomato paste, 1 cup frozen shrimps, ground black pepper
Once pasta is cooked, drain, reserving ½ cup of the pasta water. Add the pasta (with the ½ cup pasta water) to the sauce in the skillet. Return to flame, stir and cook on a medium/high heat for 1 minute. Serve straight away.
Notes
See the post above for further details
To boil the pasta, ensure the pan is filled with enough water so the pasta is fully submerged. Use a pan large enough to so the boiling water can pass around each piece of pasta. This way the pasta will cook uniformly not stick together.
It is best eaten the same day but leftovers can be stored in a sealed container and keep in the fridge for up to 24 hours (the pasta will be too starchy if it is kept for any longer).