1. In a medium saucepan, heat the butter over medium-low heat until melted.
2. Add the Gluten Free flour and whisk until smooth.
3. Over medium heat, cook until the mixture turns a light, golden sandy color, for 5 minutes.
4. Drop the roux over the baked tomato tortellini and serve hot.
Gluten Free flours vary, we don't recommend making roux much darker than blond or peanut-butter colored - this can result in a burnt or scorched taste.