Sear Paneer: Melt 1 tbsp butter and 1 tbsp oil in a large deep skillet over medium heat. Add the paneer cubes in a single layer and sear for 2 to 3 minutes, turning once, until lightly golden on two sides. Transfer seared paneer to a plate.

Sauté Aromatics: In the same skillet with remaining fat, add the cumin seeds. Let them sizzle for 20 seconds. Add the diced onion and cook for 3 to 4 minutes until soft. Stir in minced garlic, ginger, and green serrano pepper; cook for 60 seconds until fragrant.

Add Spices & Greens: Stir in ground coriander, cumin, turmeric, and salt for 20 seconds. Add the squeezed thawed spinach and 1/3 cup water or broth. Stir thoroughly, breaking up any clumps of spinach, and simmer on medium for 3 minutes.

Immersion Pulse (Optional for Silky Texture): Remove skillet from heat. Insert an immersion blender directly into the skillet and pulse 4 to 5 times (about 10-15 seconds total) to break down coarse spinach shreds into a creamy, velvety sauce. (Leave some texture; do not over-puree).

Finish with Dairy: Return skillet to low heat. Stir in the heavy cream and remaining 1 tbsp butter. Fold in the seared paneer cubes.

Simmer for 2 to 3 minutes until the paneer is warm and tender. Remove from heat, stir in garam masala, crushed kasuri methi, and fresh lemon juice. Serve hot with warm garlic naan, parathas, or basmati rice.