Place the besan in a large bowl and add salt, ground coriander seeds, chili flakes and baking soda. Slowly pour in the water, whisking it in till the mixture is consistent (it shouldn't be watery or too thick).
Heat a small saucepan (I used a 2 qt. saucepan) and add about 1/2 cup of oil or more if you'd like. Bring heat up to medium. Once the oil begins to simmer, begin to fry in small batches. Cover the spinach leaves with the flour batter and carefully drop the dredged spinach leaves on to the pan. Make sure their shape stays intact and don't overcrowd the pan. If the pakoras don't float up immediately, let the oil heat up a little more.
Fry each side till it becomes a medium brown. Flip. The timing will vary based on the heat of the pan. Bring the heat down to low if the pan begins to overheat and pakoras begin to burn easily
Transfer fried pakoras on paper towels to absorb excess oil.