Preheat oven to 350° F.
In a medium microwave safe bowl, melt butter until just melted. Add white and brown sugar and mix until combined. Beat in egg. Add vanilla extract.
Stir in gluten free flour blend, guar gum, salt, and baking soda. Combine until all ingredients are incorporated.
Add oats, chocolate chips and pecans and stir until mixed throughout.
Scoop into a 10 inch cast iron skillet and smooth the top. Note: if not using a cast iron skillet, use an 8x8 glass or metal pan, lightly coated in cooking spray.
Bake for 20 minutes. DO NOT over bake! The inside will be sightly gooey and the top will be slightly golden brown.
Remove from oven and allow to cool before slicing and eating. Best eaten the same day baked, but not too bad the day after.
Optional: serve with vanilla ice cream and chocolate sauce or caramel sauce...or both :)