• Preheat the oven to 180ºC (350°F) and grease a 9x13-inch baking dish.
• In a large mixing bowl, whisk together the flour, sugar, and baking soda. Add the milk, eggs, and vanilla extract, and beat on low speed using an electric mixer until smooth and well combined.
  2 cups all-purpose flour, 2 cups white sugar, 1 teaspoon baking soda, ½ cup milk, 2 large eggs, 1 teaspoon vanilla extract
• In a saucepan over medium heat, combine the water, butter, vegetable oil, and peanut butter. Cook, stirring constantly, until the mixture is completely smooth, about 5 minutes.
  1 cup water, ½ cup butter, ½ cup vegetable oil, ½ cup peanut butter
• Gradually pour the warm peanut butter mixture into the bowl with the batter. Stir until everything is fully incorporated and smooth. Pour the batter into the prepared baking pan, spreading it evenly. Bake for 60 minutes, or until a toothpick inserted in the center comes out clean.

For the icing:

• Melt the butter and peanut butter in a medium saucepan over medium heat. Stir until smooth.
  ½ cup butter, ½ cup peanut butter
• Add the milk and vanilla extract, then whisk in the powdered sugar until you achieve a creamy consistency, about 3-5 minutes. Add a little extra milk if needed to make it pourable.
  ⅓ cup milk, 1 teaspoon vanilla extract, 4 ¾ cups confectioners' sugar
• Pour the icing over the warm cake and spread it evenly with a spatula. Let it cool and set before slicing and serving. Serve and enjoy!