This is a recipe that one of my best friend's mom would make and I have been making for 30 years.
Chocolate Revel Bars (Gluten Free)
1 cup butter, softened
2 cups brown sugar
2 tsp. vanilla
2 1/2 cups GF flour mixture (use 2 tsp. xanthum gun if your mixture does not have it)
1 tsp salt
1 tsp. baking soda
3 cups GF oats
2 cups chocolate chips (semi-sweet or milk chocolate)
1 can of sweetened condensed milk
3 TBSP butter
Cream together butter, sugar, eggs, and vanilla.