Add 1 1/2 cups water to a medium saucepan and bring to a boil.
In the meantime, sift chickpea flour in a bowl, add salt, cayenne pepper, and the remaining 1 1/2 cups water.
Pour the chickpea flour mixture into the boiling water and stir vigorously using a wire whisk until smooth and creamy.
Reduce heat to simmer for about 10 minutes.
Remove from heat, add parsley, and stir.
Pour the panelle mixture on the prepared parchment paper and flatten with a spatula to about 1/4 inch thick.
Allow the dough to cool for at least 30 minutes to 1 hour.
After it is fully cool and dense, cut it into squares.