Shrimp Fra Diavolo

Trying to eat with minimal added sugar, flour, and dairy has brought to try some new things.
I found this recipe and it was a little spicy but SO good.

ingredients
1 tbs olive oil
1 large white onion, thinly sliced
1 tsp minced garlic
1 tsp crushed red pepper flakes
3C marinara sauce (I used Victoria All Natural Marinara)
1/2C red wine vinegar
1/4 tsp black pepper
2 lbs cleaned shrimp

directions

1. Heat 1 tbs olive oil in a large skillet over medium heat.
2. Add onion and cook 5 minutes, until soft.
3. Add garlic and pepper flakes, cook 1 minute.
4. Add vinegar, cook 3 minutes.
5. Stir in marinara and black pepper, simmer 5 minutes.
6. Add shrimp, cook until pink (time depends on if shrimp are fresh or frozen).
7. Serve over pasta if desired.
8. Enjoy!