Rinse the salmon fillets, then pat dry with paper towels.
Sprinkle the 1/2 teaspoon of salt and 1/4 teaspoon of pepper on all sides of the salmon.
Heat the olive oil in a 10” cast-iron skillet until nearly smoking hot.
Lower the heat to medium, and then add the salmon fillets.
Cook the salmon fillets on the first side until golden brown—they will release easily from the pan when they’re ready to flip.
Flip the salmon and cook the second side for 3-4 minutes.
Remove the salmon from the pan and place on a plate to rest.
Turn off the heat on the skillet. The residual heat will be enough to cook the sauce.
Add the minced garlic to the skillet, and stir for 30 seconds.
Add the spinach, tomatoes, and half and half to the skillet. Give it a stir and season with a big pinch of salt and pepper.
Nestle the salmon back into the skillet and serve, garnished with Parmesan cheese.