Cook the beet and potatoes just enough for the potatoes to be of mash able consistency and the beets to have a little bite (slightly firm).
Instant Pot Instructions for cooking beet and potatoes:
Peel the potatoes and the beet. Slice the potatoes into quarters and the beet in half. Place beet and potatoes in a steamer basket. Add 1 cup of water to the Instant Pot, and place the trivet inside. Place steamer basket on the trivet and cover the kid of the IP. Pressure Cook (or use Manual mode for older Instant Pot models) for 5 minutes and let the pressure release naturally. Once the vent has come down, open the lid of the Instant Pot and take out the vegetables. Cool them to room temperature before proceeding with the rest of the steps.
Stovetop Instructions for cooking beet and potatoes:
Peel the potatoes and the beet. Slice the potatoes into quarters and the beet in half. Heat water in a bot on the stovetop. Add the beet and potatoes, cover and cook for 20-25 minutes until the vegetables are tender. Cool them to room temperature before proceeding with the rest of the steps.
Preparing the tikkis / patties:
In a large mixing bowl, mash the cooled potatoes using a potato masher or your fingers.
Grate the cooled, cooked beet using a grater. Add the grated beet to the mixing bowl.
Add the grated ginger, corn kernels, frozen peas, garam masala, chopped mint, chaat masala and salt.
Add 4 tablespoons of rice flour, and mix all the ingredients using your palms. The ingredients should form a dough-like ball, and should not be too sticky or too dry. Add a little more rice flour, to bind the ingredients if needed.
Once the patty-dough is formed, make lemon-sized balls of the patty dough. Wet your palms with water, tap off excess water and shape the patties. Keep the shaped patties on parchment paper or on a non-stick surface after shape them.
In a skillet/ frying pan on the stove-top, add enough vegetable oil such that there is half-inch deep oil in the pan. Once hot, add the patties gently. Fry in batches, do not overcrowd.
Fry each side for 3-4 minutes until golden brown. Flip over gently and fry the other side for 3-4 minutes. Once cooked, transfer to absorbent kitchen paper.
Serve warm with tamarind chutney or ketchup.