Steam frozen bags of spinach in the microwave.
Chop paneer into ~1/2″ cubes. Put the cubes in a medium bowl along with turmeric, cayenne, a pinch of salt (<1/8 tsp), and just enough grapeseed oil to lightly coat the cheese. Mix together.
Mix spices for garam masala in the small bowl.
Remove veins and seeds from serrano peppers (if using). Finely chop peppers, garlic, and onion. Put them in the other bowl along with the garam masala and ~1/4 tsp of salt. Mix together.
Sauté paneer cubes on in the sauté pan over medium-low heat (~4 out of 10), stirring occasionally. Return to bowl once cubes are slightly browned on one side (~5min) and set aside to cool.
Add a little grapeseed oil to the sauté pan over medium-low heat (~1 TBSP) and add the onion and pepper mixture. Sauté until onions begin to soften (~3 minutes).
Add the spinach directly from the bags to the sauté pan along with the rest of the salt (~1/2 tsp), combine with the onion mixture and cook, stirring occasionally (~10 minutes).
Turn off the burner and add yogurt in 1/4 cup scoops, stirring to combine in between each scoop.
Add paneer and stir to combine.