Place the dried peas in a large bowl with baking soda. Pour in enough boiling water to cover the peas by a few inches. Soak overnight.

Next day, drain the peas and place it into a pot. Add enough cold water to cover the peas by a few inches. Bring to a boil and then down to a simmer. Simmer for 30 minutes until the peas and softened.

Season with salt and sugar.

Heat a saucepan over medium heat. Add 2 tbsp of oil and onions. Cook for 5 minutes until soft. Add the diced potatoes and enough water to come up 3/4 way up the potatoes. Bring to a boil. Season lightly with salt.

Once the potatoes are softened and most of the water has evaporated, add the chopped corned beef. Mix to combine and heat until cooked through.

Place the Mars bar in the refrigerator.

In a bowl, mix together the flour, cornstarch, baking soda, and salt. Stir in the milk.

Heat the oil over medium high heat. Dip the Mars bars in the batter and fry in the hot oil until golden brown. Serve immediately.