Preheat the oven to 350 degrees F. Grease
a 9- by 9-inch pan with butter.
together the sugar
in a large bowl. Whisk in the butter
, cocoa and vanilla
. Stir in the flour and salt. Add the chopped semisweet and bittersweet chocolates, bacon and pecans
and stir to combine.
Spread the batter
into the pan.
Bake until the brownies
are moist but not wet, testing with a toothpick, 25 to 30 minutes. They will be very fudgy. Scoop and serve warm or cool completely before cutting.