We use this homemade marshmallow cream on ice cream sundaes and the basis of homemade candy recipes. It is very soft when you first make it, and I feel that it needs to "age" a bit before using it in candy recipes. It becomes firmer after a week (much like the Marshmallow Fluff used in the fudge recipes). Though I must tell you that I have not tried this in a fudge recipe because I don't care for fudge made with marshmallow (too sweet). I do think it will work for you if you can find the ingredients. I get these in a store that sells candy-making supplies. Note: invert sugar is comprised of glucose and fructose.
Good luck.

Beat with an electric mixer on slow speed:
1 1/8 Cup Nulomoline (invert sugar)
4 1/2 Tablespoons dried egg whites

Using candy thermometer, heat the following ingredients on the stove to 210 degrees:
1 1/8 Cup Nulomoline (invert sugar)
2 1/4 Cups corn syrup

Add heated mixture to egg white mixture and beat until light. Add 1 teaspoon vanilla. Store in a covered container at room temperature in a cool, dry place.