In the same pot that you used to make the breadcrumbs, add remaining 2 tbsp of butter and melt over medium heat. Add chopped onion, 1/2 tbsp of the salt and pepper and cook, stirring occasionally until onion has softened and is very fragrant, 5-7 minutes.
Add in minced garlic and 1 tbsp of the crushed red pepper flakes. Stir until fragrent, 1-2 minutes.
Carefully add shrimp to pot in an even layer and sprinkle with other 1/2 tbsp of salt. Cook the shrimp 2 minutes on each side. Pour in the wine and allow mixture to simmer until reducted by half, 3-4 minutes.
Pour in crushed tomatoes and oregano. Stir to combine, taste for seasoning and add remaining crushed red pepper for additional heat and salt, as needed. Reduce the heat and simmer. In the meantime, Cook pasta 1 minute-less than package instructions and set aside, reserving 1 cup of pasta cooking water.
Remove sauce mixture from the heat. Add in cooked pasta, a few splashed of the pasta water and some of the grated parmesan (if using). Using tongs or large spoons, stir to combine and add more cooking water and salt, as needed.
To serve, top with toasted breadcrumbs and fresh basil and grated parmesan, if using.