Cook spaghetti until al dente is a large pot of salted water. Reserve 1 cup of the pasta water before draining.
Meanwhile, heat a large skillet over medium heat. Add butter and olive oil, and once butter is melted add the garlic, sun dried tomatoes, and pepper flakes. Cook until fragrant, about 1 minute.
In an even layer, add shrimp to the pan and season with salt. Cook about 2 minutes per side, until shrimp is opaque throughout.
Add cooked pasta to the pan with the shrimp, and toss with tongs until coated in the butter. Add pasta water as needed until the pasta is well coated.
Add parmesan and parsley, and toss to combine, adding more pasta water if needed. Season according to taste with salt.
Serve the pasta topped with crumbled feta, and enjoy!