Pour 1/2 cup water into the bowl of a stand mixer and sprinkle in the yeast. Rest for 3 to 5 min. until the yeast foams. Stir in brown sugar, salt, olive oil and vanilla. Lastly, pour in beer and let the yeast react. After bubbling stops, add 1 cup flour and, using the hook attachment, slowly knead in flour. Continue adding 1 cup of flour at a time until the dough forms into a smooth ball that pulls away from the bowl sides. Transfer dough to a lightly oiled bowl; cover with a towel and let sit in a warm area of the room. Allow to rise and double in size (about an hour). Preheat oven to 425 degrees. Grease 2 baking sheets and set aside. Pour remaining 4 cups of water and baking soda into a large saucepan and bring to a boil. Meanwhile, divide dough into 12 equal sized balls. Roll each ball into a 1/2-inch thick long rope. Curve each into a “U” shape and cross over the ends into a classic pretzel shape. Working one by one, boil each pretzel for 30 seconds. Remove each with a slotted spoon and place 4 inches apart on a greased baking sheet. Lightly brush each pretzel with the beaten egg and sprinkle with Ghost Pepper Salt. Bake 15 to 18 min. until golden brown. Immediately brush with butter and serve.