Place the chaat masala, red chili powder, dried mango powder and salt in a medium sized bowl. Mix the spice mix and set aside.
To make fresh French fries: Peel the potatoes. Wash and cut into French fries. Soak the sliced potatoes in water, and let them sit for about 5 – 10 minutes. This step removes the excess starch in potatoes. Drain the potatoes, and lightly pat dry. Heat the oil in a karahi, wok or shallow frying on medium high heat.
Once the oil is ready, add the sliced potatoes and fry till the potatoes are golden brown in colour.
Use a slotted spoon to remove the fries from the hot oil, and place them on kitchen towel to drain the oil.
To make frozen French fries: Frozen French fries can be made on the stove, in the airfryer or the oven. Prepare the frozen fries as per the instructions at the back of the packet. I prefer making frozen French fries using the air fryer.
Place the cooked French fries in the bowl with the spice mix. Make sure that the potatoes are hot, as that will help the spice mix stick properly. Cover the bowl with a plate, or a lid and then shake vigorously for about 30 seconds. Take off the cover, add lemon juice and then give the French fries another toss.
Serve the spicy chili French fries / masala fries hot with ketchup and chai.