You can try many variations with frankie and add all the veggies which are usually not eaten but in they way of frankie wont be neglected.
I have tried this basic yet flavorful aloo cheese frankie and the recipe inspiration is Chef Sanjyot Keer. Adding some tomato ketchup in the filling is a really good idea , it enhances the taste.
Recipe:
(Makes 4 Frankies)
Ingredients:
For Rotis:
For Rotis:
- Wheat flour-1 cup
 - Salt-1/2 tsp
 - Oil-1/2 tsp
 - Water - enough to knead a soft dough
 
For Stuffing:
- Potatoes-3(boiled and mashed)
 - Ginger,garlic and green Chili paste-1 tsp
 - Coriander-1 tbsp
 - Salt
 - Turmeric-1/4 tsp
 - Chili powder-1/4 tsp
 - Tomato ketchup - 1 tbsp
 - Garam masala powder - 1 tsp
 
Other Ingredients for assembling :-
- Chopped onions-1/2 cup
 - Schezwan chutney-4 tbsp
 - Grated cheese-2 cubes
 - Vinegar with green chilies / Lemon juice -2 tbsp
 - Chat masala-1 tbsp
 
For making Rotis:
- Knead a dough with wheat flour,salt ,oil and water.
 - Cover and keep aside for 10 mins.
 - Now roll out thin rotis ( the size should be approx 8' diameter ) from the dough and cook 70% on a hot tawa without oil.
 
For the Filling: 
- Heat oil in a pan. Add ginger garlic green chili paste and saute for 30 seconds.
 - Add spices , ketchup and salt.
 - Add potatoes and coriander and mix properly.
 - The stuffing is ready. Let it cool.
 - Make long rolls from stuffing( long enough to stuff in the roti vertically) and put on oiled tawa.
 - Roast them till brown from both sides and keep aside.
 
Now to assemble the Frankie :
- Take a roti , warm on hot tawa for 30 sec.
 - Apply schezwan chutney on the roti ,keep one long potato roll vertically.
 - Put vinegar with green chilies / lemon juice all over and add chopped onions on top of the potato roll.
 - Then sprinkle chat masala and lastly grated cheese.
 - Roll and wrap in an aluminium foil or tissue and its ready to serve.
 
Notes:
My family personally does not like maida rotis for frankie and so i always make wheat rotis/ chapati , but you can try as per the preference.