Simmer sauces can be found at most grocery stores and are great for making curry. I like to add some chicken or vegetables to a small crockpot and dump the simmer sauce in. Then I heat on high for 3-4 hours. When you are using a vegetable like a potato, longer is better so they have time to cook through. My go-to vegetables are: 1 chopped potato, 1 chopped zucchini, 1/2 small onion. You can also use mushrooms and bell peppers.
I always have simmer sauce in my pantry. It’s perfect for a quick meal prep and never disappoints. I’ve never seen a simmer sauce that isn’t gluten free but always check your labels.