Method

1. Cream brown sugar and butter together until light and fluffy.
2. Add egg and vanilla, and mix until combined.
3. In a separate bowl mix together dry ingredients. Slowly add into wet ingredients and mix until combined.
4. Press mixture into a 9×13 lined with parchment, non-stick foil, or well prepped with baking spray.
5. Using a double boiler, or a pot with an inch of water and another glass or metal bowl on top of it.
6. Simmer water underneath, and add condensed milk, chocolate, and butter to top bowl.
7. Stir until melted and combined.
8. Pour chocolate mixture over bars in prepped pan.
9. Bake at 350 for 12-18 minutes, or until a toothpick comes out clean.