Congo Bars

I never eat congo bars yet. Would love to try some one day. The pictures above were from my sister. She made congo bars last week. Here are the ingredients for the congo bars. She modified a bit so the taste not too sweet.

150gm butter (e.g anchor or scs)
200g brown sugar
3 eggs size A
320g all-purpose flour (can use superfine)
2 1/2 tsp of baking powder
1 tsp vanilla essense
200g chocolate chips
50g walnut (chopped and toasted) 
sprinkle  the almond to the mixture before it put to the oven
Use pan size  10x 10

Note: Preparation similar to cake.