Irish Caramel and Vanilla Fudge

grease an 8x8 pan very well set aside in a heavy sauce pan {Dutch oven would be best} melt the butter over a low heat add the brown sugar and stir on low heat till completely melted then raise the heat to medium high and bring to a boil continue boiling until the thermometer reads HARD CRACK 336 degrees this takes about 10-15 min keep an eye on the sugar and still often during this stage {if you don't have a thermometer boil 10-15 min and test by pouring a spoon full into a small bowl with water and if strands that can be cracked appear it is ready} once it reads hard crack remove from the heat and pour in the condensed milk and whisk this may be hard to whisk at first but the heat will melt the milk and it will become easier to whisk then place back on the stove at medium heat and cook for a few min to really let that milk incorporate remove and add the vanilla mix in pour into prepared pan and let cool cut into squares and serve Enjoy!