Original recipe:

http://www.food.com/recipe/chocolate-oat-square-extravaganza-263499

I changed it a bit.

Ingredients:

Butter 80g

Brown sugar 120g

Egg 1

Vanilla 1/4 tsp

Oats 1 cup

Flour 100 g

Salt 1/4 tsp

Baking soda 1/4 tsp

Filling:

1/3 can sweetened condensed milk, around 100g

Chocolate chips 1 cup

Butter 1 tsp

Salt 1/4 tsp

Chopped walnuts 1/3 cup

Vanilla 1/4 tsp
1. Cream brown butter and  brown sugar till light and fluffy.

2. Beat in egg and vanilla.

3. Combine oats, flour, salt, and baking soda. Stir into butter mixture.

4. Press 2/3 batter into pan as base.

Filling part:

1. In a saucepan, melt butter, chocolate, with sweetened milk and salt. Stir evenly.

2. Turn off the stove. Stir in walnuts and vanilla.

3. Spread filling over the Oat base in the baking pan.

4. Sprinkle the rest 1/3 Oat batter over the filling.

5. Preheat oven to 180 degree C and bake for 25mins.