Heat a large pot of salted boiling water over medium heat. When water is boiling, cook linguine for 10 minutes, until al dente. Remove one cup of pasta water before draining pasta. Set pasta aside.

Heat a large pan over medium heat. Add onions, unsalted butter, and olive oil to the pan. Sauté for 10 minutes, until the onions are translucent.

Add garlic and shrimp to the pan and sauté for 3-4 minutes, until shrimp are pink. Remove shrimp from the pan.

Add white wine to the pan. Reduce heat to low and simmer for 5 minutes.

Stir in tomato paste, salt, and black pepper. Add linguine and a few tablespoons of pasta water to the pan and toss in the sauce. Top with shrimp and Italian parsley or fresh basil, and serve.