Sauté onions, garlic, and ginger until softened.
Add chopped fresh Roma tomatoes (or 1 (28 oz) can of whole tomatoes) and simmer uncovered for about 30 minutes.
Stir in garam masala, Kashmiri chili powder, and sugar.
Simmer a little longer, then use an immersion blender to puree the sauce until smooth.
Adjust seasoning with salt, then stir in heavy cream and a few tablespoons of butter.
Add kasori methi leaves.
