Place the heavy cream in a chilled mixing bowl. Beat using a mixer on medium high speed until stiff peaks form.
Add the sweetened condensed milk and stir gently to combine.
Add the caramel sauce, salt, and vanilla and mix gently.
Fold in the toffee and pretzel pieces.
Pour into a loaf pan and sprinkle with additional toffee pieces and pretzel pieces if desired.
Put a piece of plastic wrap on top and freeze for 4-6 hours or overnight.