Peanut Butter Fudge - cooking recipe

Ingredients

1 box light brown sugar
1 small ???
1/2 stick butter
1 tsp. vinegar
1 (12 oz.) jar peanut butter
1 tsp. vanilla flavoring

Preparation

Cook first 4 ingredients over medium heat.
After it comes to a boil, continue to boil about 5 minutes or until a small ball forms if dropped in water.
Remove from heat and stir in peanut butter and vanilla.
Mix well and pour in buttered dish.