In a large pot over medium heat, add the onions with a splash of water. Cook while stirring for 6-7 minutes until the onions have softened and have become translucent. Add the carrots and a few splashes of water and cook for another 10 minutes, stirring occasionally and adding more water if anything is sticking.
Add split green peas, 4 cups of the water, bay leaves, sea salt and pepper. Bring it to a boil, then simmer uncovered, stirring occasionally, until the peas are broken down. This will take about 1 ½ hours.
Peas absorb a lot of water, so add the remaining 1 cup of water as they are breaking down to thin the soup. Add water a little at a time to get the soup to the thickness you like. (I like mine a bit thick).
Preheat the oven to 350° F.
Place the bread chunks in a large bowl and add a few shakes of onion, garlic and sea salt.
Place on a baking sheet and pop it in the oven (or toaster oven) for about 20 minutes or until they are golden brown and crispy, flipping the croutons occasionally so they toast on both sides.