For an individual cup of hot chocolate:

1. Add 1 tbsp of cocoa, 1 tbsp sugar and 3/4 cup to 1 cup of milk into a saucepan on the stove.
2. Heat over low on the stove, whisking often.
3. Pour into a mug, add marshmallows and enjoy!

Make a Jar for your Pantry:

1. If you want to keep the hot chocolate mixture ready to use, you can make a jar of it and keep it in your pantry.  It will last for months.  Just add equal parts cocoa and sugar to the jar, and mix well.   Then add to milk when you want a cup of hot chocolate.