Heat the olive oil in a frying pan over medium heat. Season both fillets with salt and pepper. Add salmon to the pan, skin side up. Sear for 2 minutes, then flip both fillets. Let cook another 2-3 minutes until salmon is just undercooked. Remove from pan and transfer to a plate.
In the same pan, add butter, garlic, and onion. Cook for 2-3 minutes until onions are cooked through. Add tomatoes and cook until they are beginning to blister, about 2 minutes. Add spinach and cook until it starts to wilt.
Add chicken broth, heavy cream, parmesan and stir. Create two indents in the mixture and transfer the salmon back to the pan, skin side down. Let cook 2-3 minutes until salmon is done.
Remove from heat and enjoy! I like to serve this over roasted potatoes, or brown rice!