To make the roux, combine the flour and spices in a small bowl. In a pan, over medium-high heat, melt the butter. Add the flour and spices to the melted butter.
Mix together until the flour has absorbed all the butter. Add the tomato paste, tonkatsu, and honey. Turn off the heat and set aside.
Place a deep pot over medium-high heat. Saute the onions and garlic with 1 tablespoon of vegetable oil until softened, about 5 minutes. Season with salt and pepper.
Add the carrots, chicken stock, water, and bay leaves. Bring to a boil, then reduce to a simmer.
Add the potatoes. Place the lid slightly ajar and simmer for 30 minutes. Occasionally skim any foam that appears.
Take a small portion of the roux and place it in a ladle. Place the ladle in the liquid of the pot and slowly mix in the roux. This will have to be done in several batches. Take your time to make sure it mixes well together.
Finally, add the yogurt and mix well.