METHOD TO PREPARE

Strain the yogurt overnight using a cheesecloth to make it thick and spreadable.
In the morning, add the strained yogurt to a bowl along with cream cheese, vegetables, and seasoning. Mix well until everything is combined. Taste and adjust the seasoning if needed.
Store the spread in the fridge if you're not using it immediately.
Spread a generous amount of the yogurt mixture onto a slice of whole wheat bread and top with another slice.
Heat a skillet over medium heat. Add oil, and when it's hot, add mustard seeds and curry leaves. Once the mustard seeds pop, add butter and place the sandwich in the pan. Let it toast until golden brown. Flip and cook the other side until toasted.
Repeat the process for the remaining sandwiches, preparing the tadka (tempering) again for each batch if necessary.
The tadka is optional but adds extra flavor to the sandwich.
This sandwich works great for a lunchbox. Any leftover yogurt spread can be enjoyed with crackers as a delightful snack.