Preheat the oven to 375°F. Butter a 9x13-inch baking dish, dust with flour and shake excess flour off.
In a double boiler or water bath, melt the butter with the chocolate, stirring occasionally until completely mixed.
In a small cup, combine the instant coffee with the coffee liquor or water, stir until almost dissolved and pour into the chocolate mixture, it will finish dissolving in the melted chocolate. Mix with a spatula and remove from the heat. Let cool.
In a medium mixing bowl, beat the eggs with a fork or whisk until they have gained some volume and seem foamy. Add the sour cream, vanilla and sugar. Mix with a spatula until thoroughly combined.
In a large mixing bowl, combine the all-purpose flour, baking powder and salt. Stir.
Slowly pour the chocolate mix into egg mixture, mixing with a spatula as you do, until completely combined. Pour that mixture into the dry ingredients and mix until thoroughly combined. Finally, toss in the caramelized pecans and gently fold. Pour into the prepared baking dish and place in the oven. Bake for 20 minutes or until the top has lightly crisped, and the brownies are still moist but not wet (test with a toothpick).
Remove from the oven, let cool and slice into squares. Sprinkle with confectioners’ sugar, if desired.