Add everything through the black pepper to a pot, bring to a boil, then reduce heat and simmer, covered, until the vegetables are tender, about 30 minutes, stirring occasionally.

In a small bowl, whisk together the flour and cold water until smooth.

When vegetables are tender, add peas to the pot and stir. Let them heat up for a minute or so. Now add the flour mixture and stir. Continue to simmer until the stew thickens.

Taste for seasoning and adjust if needed. Serve topped with parsley, if desired.