Boil the maize and bean in a pressure cooker at medium heat.

In a sufuria place the onions and cooking oil. When the onion turns golden brown add the chopped tomatoes and cover the sufuria.

Uncover the sufuria and crash the tomatoes until it becomes pasty then add the maize and beans and stir. Add the salt and stir and add 1/8 of a glass of water so that the githeri does not burn then turn off the heat.