Hi Heather, When making baked goods, you have to be a little bit careful about substitutions. It’s probably not a good idea to substitute just milk for the cream in Nana's Banana Bread because the fat content of milk and cream is different. However, you could use a combination of milk and melted butter instead of cream. For the 1/2 cup of heavy cream in the recipe, try substituting 6 tablespoons milk plus 2 1/2 tablespoons melted butter.