monster cookies recipe

1 cup unsalted butter, softened - 1 1/2 cups packed light brown sugar - 1 cup granulated sugar - 1 1/2 cups creamy peanut butter - 3 large eggs - 1 teaspoon vanilla extract - 4 1/2 cups old-fashioned rolled oats - 2 teaspoons baking soda - 1/2 teaspoon salt - 1 cup semisweet chocolate chips - 1 cup M&M candies