This recipe seems simple to follow.

PENNE ALL'ARRABBIATA (ENRAGED PENNE)
Source: Nonna's Italian Kitchen: Delicious Homestyle Vegan Cuisine by Bryanna Clark Grogan

1 lb penne rigate or other tubular pasta
1/4 cup extra virgin olive oil
6 to 8 cloves garlic, chopped
1/2 tsp dried red pepper flakes
2 lb ripe plum tomatoes (or 28 oz canned italian plum tomatoes)
1/2 tsp salt
1/4 cup chopped fresh italian parsley

Put a large pot of salted water on to boil for the pasta.

In a large, heavy skillet or pot, heat the oil over medium heat. Add the garlic and red pepper flakes and stir just until the garlic begins to change colour. Remove from heat.

Mash up the tomatoes with a food processor (use pulse mode to keep them a bit rough) or chop them up and mash by hand, reserving juice. You can also use commercial crushed tomatoes but not pureed tomatoes. Add tomatoes to pan. Place the pan back on the heat, add the salt and simmer uncovered while you cook the pasta to al dente stage.

Taste the sauce for salt, drain pasta and add it to the sauce. Toss well and let it cook in the sauce for a minute or two. Sprinkle with parsley and serve.