Preheat the oven 350 degrees Fahrenheit. Grease a 13 inch by 18 inch pan.
In a medium saucepan add water, butter, oil, instant coffee, and Dutch-processed cocoa bring mixture to a boil over medium-low heat.
In a small bowl stir together the gluten-free flour, sugar, baking soda and salt.
In another bowl, whisk together the sour cream and eggs.
Fold the egg mixture into the flour mixture.
Once the chocolate mixture is boiling, remove from heat and pour into the batter. Continue to stir until no lumps remain.
Pour the batter into the prepared pan and smooth it out with a spatula to make sure it is an even layer.
Bake for 18-20 minutes or until the cake is set.
When the cake is halfway through cooking, prepare the frosting.
Measure the confectioner’s sugar into a bowl and set aside.
In a saucepan, melt the butter. Add the cocoa and stir to combine. Remove from heat and stir in the milk.
Pour the chocolate into the bowl with the powdered sugar. Stir together until no lumps remain. Stir in the chopped pecans.
Pour the frosting over the top of the cake. Use a spatula to gently spread the frosting over the top of the warm cake.
Allow to cool completely and set. Cut into squares and enjoy!