Simple Brownies

Source: Country Fair Cookbook
Makes 15.
Ingredients
3/4 cup butter (170g) (I used half-fat butter and it worked perfectly)
1 1/2 cup sugar (340g) (granulated is fine)
2 eggs
1 tsp vanilla
1/2 tsp chocolate extract (optional)
3/4 cup sifted flour (90g)
1/2 cup cocoa (55g)
1/4 tsp salt
3/4 cup chopped walnuts
Preheat oven to 180C/Gas Mark 4. Grease a 9″ square tin.
Method
1) Cream together butter and sugar until light and fluffy. Add eggs and vanilla; beat well.
2) Sift together flour, cocoa and salt. Add to creamed mixture, blending well. Stir in walnuts if using. Spread evenly in tin.
3) Bake for 35 minutes or until done–a wooden toothpick or skewer inserted in the middle should come out almost clean, with just a couple of crumbs clinging to it. Cool in tin on rack. Cut 2 3/4 x 1 3/4 inch bars when cold.