Texas sheet cake - chinese grandma

Ingredients

• 2 cups sugar
• 2 cups flour
• 1 teaspoon baking soda
• 1/4 teaspoon salt (1/2 teaspoon salt if using unsalted butter)
• 1/2 cup butter
• 1/2 cup vegetable oil (or you can use another 1/2 cup butter)
• 1 cup water
• 1/4 cup cocoa
• 1/2 cup sour cream, plain yogurt or buttermilk (or combine 1/2 cup regular milk with 1 teaspoon white vinegar or lemon juice – let sit for a minute before mixing into batter)
• 2 eggs
• 1 teaspoon vanilla
• 1/2 cup butter (add 1/4 teaspoon salt if using unsalted butter)
• 1/3 cup milk
• 1 box (1 pound) confectioners’ sugar, about 4 cups (sift if you want a perfectly smooth frosting)
• 1/2 teaspoon vanilla
• 1/2 cup chopped pecans, optional