Combine milk, sugar, ground cinnamon, vanilla extract and raisins in a small sauce pan. Mix to dissolve the sugar, then add to medium heat and bring to a boil. While milk mixture comes up to a boil, reduce the heat to low and simmer until ready to use.
Next, add a pan to medium heat. Then add the gluten-free all purpose flour. Toast/parch (continuously stirring to avoid burning) until flour is light brown in color (5-8 minutes) It may not get as dark as wheat flour, but you will notice a change in the color.
Then remove from the heat and sift, over a fine mesh sieve to remove any lumps. Return the sifted flour to the pan and return to medium-low heat.
Create a space in the center of the flour so that you can see the bottom of the pan. Then add the butter. Ass the butter melts, mix in the flour until the mixture is crumbly.
Then add the milk that is simmer on low heat, a little at a time to the crumbly flour and butter mixture flour and mix in. Continue to cook on low, continually stirring. Until you have a smooth consistency. Then remove from the heat and allow to cool before serving.