Preheat oven to 350°F (175°C). Grease a 10 x 15 x 1-inch baking pan.

In a large bowl, mix oleo (or melted butter) and sugar until thoroughly combined.

Add eggs one at a time, then stir in vanilla extract. Beat until light and fluffy.

In a separate small bowl, sift together cocoa, flour, salt.

Gradually add the sifted dry ingredients and milk to the egg mixture, alternating between the two. Mix until just combined; do not overmix.

Stir in chopped nuts.

Pour batter into the prepared baking pan, spreading evenly.

Bake for 20 minutes, or until a toothpick inserted into the center comes out with moist crumbs.

Let cool slightly before cutting into squares and serving.