After using the 2 tablespoons of whipping cream in Penny's sugar cookies. Can the rest of the unused cream be frozen??? or what do you all do with it, since the smallest I am able to buy is 1/2 pint?

It can't really be frozen. However you could use it to make ganache, then freeze that. equal parts cream/chocolate and a bit of butter and you have ganache, chill it and shape it an you have truffles.

Now that you have made the cookies with cream, try it with milk and compare the results. The 2 TBPS of cream my not be requied for a satisfactory cookie- just a suggestion.