This is a very easy sauce to make using a curry powder; I prefer the Madras curry powder. If you’re adventurous and want to make your own curry powder, there are a number of recipes and videos on-line (YouTube especially) which show the process.
In a small sauce pan, heat
2 tablespoons oil
1 teaspoon to 1 tablespoon of curry, depending on your taste and cook for approximately 30 seconds until you can smell the curry.
Add 2 tablespoons all purpose gluten-free flour. Whisk and cook for several minutes.
Whisk in 3/4 to 1 cup (the amount of milk depends on how thick you want your sauce) of your favorite milk (coconut milk works great here but rice, hemp, almond also work fine).