If using regular curd, strain it in muslin cloth for 15-20 minutes to remove excess water. This gives thick consistency.
Heat oil in a pan, add mustard seed and cumin seeds. Let them splutter and add green chilli, chopped onion, and sauté until soft then mix in turmeric powder and red chilli powder and stir well
Add crumbled paneer, grated carrot, and salt. Cook for a minute, then turn off the heat.
Let the tadka cool slightly before mixing it with the thick curd. Stir well to combine everything.
Spread the dahi tadka mixture evenly on one slice of bread and place another slice on top to make a sandwich
Toast on a pan with a little butter or ghee or grill it for a crispy texture.
Cut into halves and serve with mint chutney or ketchup and enjoy this protein rich, flavorful sandwich.