Spray a 13x9 casserole dish with nonstick cooking spray. Pour in the pretzels and arrange as best you can in an even layer. Top with banana slices (optional)
Combine remaining ingredients (sugar, corn syrup, butter, cream, and vanilla) in a large (nonstick if possible) saucepan
Over medium heat bring to a boil stirring slowly. Be patient!!! If you have a candy thermometer boil until it reaches 250. If you don't, wait until it reaches a milky caramel color and is smooth, sticking together a bit but still drizzles off the spoon.
Quickly pour caramel over pretzels and bananas(if used). Stir if needed within the casserole dish to distribute evenly. Let cool, cut with knife or just break, and enjoy!!!