Here is a simple and tasty instant dosa recipe. Fermenting is not needed.
Ragi flour (millet flour) - 1 cup
Wheat flour - 2 cups
Rava - 2 tablespoon
Butter(preheated) - 1 tablespoon
Mix all the ingredients except oil/Ghee.
Mix water to bring it into dosa batter consistency.
Add oil/ ghee to make it into crispy dosas.