In a small bowl mix most of the spices, coconut powder, sesame powder, coriander powder, fennel seeds powder, red chili, turmeric, salt, and sugar. Set aside.
In a wide frying pan heat the oil moderately over medium high heat, add cumin seeds as seeds crack add asafetida. Add bell pepper mix well lower the heat to low medium. Cover the pan and let it cook for about 3 minutes.
Sprinkle the spice mix. Mix it well coating all the bell pepper. Let it cook about 3-4 minutes covered, do stir in between. Cook the bell peppers until they are tender but still little crisp.
Turn off the heat, add the mango powder and lemon juice mix well.
Masala bell pepper is ready.