Buttermilk Brownies (aka Texas sheet cake)

These are so yummy- I got this recipe from Linda and they are the best (melt in your mouth-truely)

Sift together:
2 cups sugar
2 cups flour
3 T cocoa

Bring to boil:
1 cup cold water
1/2 cup margerine
1/2 salad oil
add to dry ingredients beat until creamy
Add 1/2 cup buttermilk (I put 1 T lemon juice in a measuring cup and add enough milk to make 1 cup and wait a few minutes because I rarely if ever by buttermilk use 1/2 then use another 1/3 in frosting-dispose of the rest)
2 eggs
1 tsp soda
Beat thouroghly- pour into cookie sheet size pan
Bake @ 350 for 18 min (don't overbake)

Frosting;
Bring to boil
1/2 cup margerine
1/3 cup buttermilk
3 T cocoa
Pour into mixing bowl and beat in 4 cups (usually a bit more) powdered sugar
Beat until smooth and add 1/2 tsp vanilla
Spread over warm brownies