In a large deep skillet or pot, heat the olive oil over medium heat.
Add the chopped onion and minced garlic to the pot and sauté for 3-4 minutes until the onion becomes translucent and fragrant.
Add the penne pasta, water, chicken broth, salt, black pepper, and crushed red pepper flakes to the pot. Stir to combine.
Bring the mixture to a boil over high heat, then reduce the heat to medium-low and simmer uncovered.
Cook for 10-12 minutes, stirring occasionally, until the pasta is al dente and most of the liquid has been absorbed.
Add the halved cherry tomatoes and Boursin cheese to the pot. Stir well until the cheese is fully melted and the tomatoes are warmed through.
Remove the pot from heat and stir in the chopped fresh basil and grated Parmesan cheese.
Taste and adjust seasoning with additional salt and pepper if needed.
Serve immediately, garnished with extra basil or Parmesan if desired.