Preheat oven to 350°. Place butter in a 9-inch square baking dish, and place dish in oven just until butter is melted.
In a medium bowl, whisk together ¾ cup sugar, flour, and 2 tablespoons cocoa. Whisk in milk and vanilla until smooth. Pour onto melted butter in dish; do not stir together.
In a small bowl, stir together pecans, toffee bits, remaining 1 cup sugar, and remaining 4 tablespoons cocoa; sprinkle onto batter. Slowly pour 1½ cups boiling water onto batter; do not stir together.
Bake until top appears dry and set, 40 to 50 minutes. Let cool for 20 minutes; serve with ice cream, caramel, and pecans, if desired.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/chocolate-pecan-cobbler-recipe/