Heat the oil in a large pot over medium heat.
Add the onion, carrots, and celery and cook for 5 minutes, stirring occasionally, until softened.
Add the garlic and cook for 1 minute, until fragrant.
Stir in the butter, tomato paste and flour and cook for 1 minute, stirring constantly.
Slowly pour in the broth about ½ cup at a time, stirring well and allowing the mixture to come back to a gentle simmer between additions. Continue until all the broth is used.
Add the potatoes, Italian seasoning, and bay leaf, then bring the stew to a boil. Adjust broth level at this time to your preference.
Reduce heat and simmer uncovered for 20–25 minutes, until the potatoes are tender and the stew has thickened.
Stir in the cream and cook for 2–3 minutes until warmed through.
Remove the bay leaf and season with salt and pepper to taste before serving.