Step 1

Preheat the oven to 350F.

Step 2

Line an 11x7 inch baking pan with parchment paper and set aside.

Step 3

In a large bowl cream the butter and brown sugar until light and fluffy.

Step 4

Add the eggs and vanilla and beat well.

Step 5

Add the flour, rolled oats, baking powder, cinnamon and salt to the creamed mixture and beat to combine. The batter will be quite thick.

Step 6

Stir in the apples and nuts (nuts are optional).

Step 7

Spread batter evenly in the prepared pan.

Step 8

Bake for 30 to 35 minutes until golden brown and center is almost firm.

Step 9

Allow pan to cool completely on a wire rack. Dust top with powdered sugar.

Step 10

When cooled, lift the squares out with the parchment paper and cut into 12 equal squares.