In a large pot (I use a dutch oven), saute the onion, garlic, and celery for about 5 minutes on medium heat. It shouldn’t stick due to moisture from the vegetables, but if some sticking occurs, add a bit of water.
Add the carrots and continue sautéing for about 10 more minutes.
Add everything else except the peas, flour, and water. Mix thoroughly, then cover and bring to a boil. It is okay if the broth does not completely cover all of the veggies. If you add more broth, your stew will likely end up being too thin. Lower the heat to a simmer and put the lid on. Simmer for about 20 minutes.
After 20 minutes, mix in the frozen peas.
In a small bowl, add the flour and cold water. Mix it thoroughly until it is smooth with no clumps. Then pour this mixture into your pot and stir on low heat until the stew has reached your desired consistency.