One of my favourites. A recipe gift from a very good friend and something I made often when my children were growing up.

Ingredients

1/2 cup margarine (115g) (I use butter)
1 1/4 cup of sugar (240g)
1/4 cup peanut butter, creamy (45g)
1 tsp pure vanilla
2 large free range eggs, beaten
2 cups plain flour (200g)
1 TBS (yes) Baking Powder
1/2 tsp salt
1 cup milk (8 fluid ounces)
Peanut Butter Frosting (See below)
chopped toasted walnuts to garnish

Peanut Butter Frosting

Creamy and peanut buttery. Delicious!

1/4 cup margarine (57g) (again, I use butter)
1/4 cup peanut butter, creamy (45g)
1 tsp pure vanilla
2 1/2 cups of icing sugar (325g)
1/4 cup milk (2 fluid ounces)

Directions

Preheat the oven to 180*C/350*F/gas mark 4. Butter and flour a 9 by 13 inch baking tin, shaking out any excess flour.
Cream together the butter and sugar, until light and fluffy. Beat in the peanut butter and vanilla. Beat in the eggs a bit at a time. Whisk together the flour, baking powder and salt. Add alternately to the creamed mixture, beginning and ending with flour and mixing well after each addition. Pour into the prepared pan, smooth over the top.
Bake for 30 to 35 minutes, until risen and a toothpick inserted in the centre comes out clean.
Remove to a wire rack to cool completely, leaving it in the pan.
Once cooled, ice with the peanut butter frosting and sprinkle with chopped nuts. Cut into squares to serve.

Peanut Butter Frosting

Cream together the butter and peanut butter along with the vanilla. Add the sugar alternately with the milk, beating until light and fluffy. You may need more or less milk. It all depends on the weather. Judge accordingly.