Make the sauce: Make a roux by melting ½ cup butter and whisking in ½ cup of flour until lightly browned (~30 seconds). Stir in 4 Tbsp curry powder, 3 Tbsp umami sauce, and tomato paste, remove from heat, and set aside.
Prepare the rice: Cook the rice according to package while your veggies stew.
Make the stew: Sauté onions in oil until they start to brown. Add diced winter veggies, remaining curry powder and umami sauce, garlic, ginger, 1 Tbsp soy sauce and sauté for 5 minutes to release the flavors. Add vegetable stock and cook until soft (~10-15 minutes), add your curry sauce from before, and simmer for another 5 minutes until the sauce thickens.