These rich cookie bars take just 5 ingredients to make. No bowl required! Make them whatever flavor you'd like. Our family favorite!!
Heat oven to 350F. Place butter or margarine in 9x13 inch glass or a not-non-stick metal baking pan. Melt butter in the preheating oven. (See note below.) This only takes about 5 or so minutes. Remove pan from oven. Carefully spray the sides of the pan with cooking spray to prevent sticking.
Tilt the pan to evenly spread the butter throughout the pan. Sprinkle graham cracker crumbs over melted butter, creating a crust. (Be careful - the pan may be hot!!) Spread evenly out and pat gently.
Top crust with, and spread out, sweetened condensed milk. Top with both bags of chocolate chips.
Bake 25-30 minutes, until edges are slightly browned. You can bake until the sweetened condensed milk is browned if you'd like, but it will make the pan harder to clean.
Cool slightly, and cut bars while slightly warm. They'll be too hard if they cool completely. I like cutting them rather thin and small. Try not to eat them all in one sitting.
Be sure you get sweetened condensed milk, which is thick since it has sugar cooked into it. It is NOT the same as evaporated milk, which is unsweetened.
Use a glass or natural aluminum (not non-stick) pan with flat, not sloped, sides. This makes for the best crust and easiest clean-up.
Be careful handling a hot pan!
If you're nervous about making a crust in a hot pan, melt the butter in the microwave or on the stove, stir in graham cracker crumbs, and pan evenly into a room temperature pan. Proceed with layering the sweetened condensed milk and chocolate chips; bake normally.