Cut the paneer into 1-inch cubes. In a medium bowl, mix the turmeric, cayenne, salt, cinnamon, and 1 1/2 tablespoons olive oil. Add the paneer and toss to coat. Let marinate for 20 minutes.
In a 10-inch skillet over medium-high heat, heat 1/2 tablespoon olive oil. Add the paneer with any leftover marinade. Sear for 2-3 minutes on one side, then flip and cook another 2 minutes. Transfer to a plate.
Reduce heat to medium-low. Add the remaining olive oil to the same skillet, then add onions, ginger, garlic, and jalapeños. Cook, stirring occasionally, until caramelized, about 8 minutes.
Add the butter. Once melted, stir in coriander, cumin, and garam masala, and cook for 1 minute.
Stir in the spinach with a splash of water. Cook for 3 minutes, stirring often.
Remove from heat and stir in the yogurt. Return the paneer to the skillet, cover, and cook on low for 2 minutes.
Homemade Paneer: Use our easy small batch paneer recipe, which makes just the right amount for this dish. Store it covered in the fridge for up to 5 days.
Garam Masala: If store-bought is hard to find or pricey, make your own with our small batch garam masala recipe. It adds rich flavor to this dish and works well with chicken and fish too. The recipe makes 1/4 cup to keep on hand.
Pan-Frying: Sear the paneer in spices before adding it to the spinach. This helps it hold its shape and boosts the flavor.
Drain Frozen Spinach Well: If using frozen spinach, squeeze out as much moisture as possible to avoid a watery sauce.