Preheat oven to 350.
In the bowl of a stand mixer with a whisk attachment add the butter and brown sugar, beat on high until well combined.
Add the egg, yolk and vanilla extra, mix until well combined, light and fluffy.
Add 2 tablespoons stout, stir until combined.
Sprinkle the flour and salt over the butter mixture, stir until combined.
Spread evenly into a greased 8X8 baking pan.
Bake at 350 for 22-25 minutes or until the top is golden brown. Allow to cool completely.
In a pot over high heat add the butter, brown sugar, white sugar, corn syrup, heavy cream and ¼ cup stout. Stir until the butter has melted and the sugar has dissolved.
Allow to boil until a dark caramel color and reached 248 degrees on a candy thermometer, about 8 minutes. Allow to cool for ten minutes.
Pour over the blondies layer, chill until set, about 3 hours.