Add frozen peas in a bowl and cover with water. Microwave for 1 minute. Strain the water out and let the peas cool.
When the boiled potato is cooled down, peel it. Cut ¼ of potato and put it on the side. Then using a grater, grate the remaining ¾ potato. Add salt to this grated potato and mix it evenly.
Grate the ¼ potato that we had separated and put it in a separate bowl. Add peas and all the spices (fennel powder, garam masala powder, red chili powder, roasted cumin powder, amchur/mango powder, and salt) and mix well.
Divide the plain-salted potatoes into 4-5 equal parts. Do the same with the spicy potato- peas mixture.
Take one part of potato & salt mixture and flatten in your palm using your fingers. Now, add potato and peas mixture in the center of this. Next, wrap the outer layer of the plain-salted potatoes over this spicy inner core. Roll it softly into a ball and then flatten it like patties using your palm pressure. In the same way, prepare all the tikkis.
In a medium sized skillet, add oil and ghee. Once it is hot, add all the Tikkis and fry them till they turn golden on both the sides.