My children love making there with me. Not every time we have left over mashed potatoes do we make them for they are messy, but we probably make them once every other month. They love making there own shapes.
Mix potatoes, sugar, eggs and salt. Mix in milk and other ingredients. Roll pretty flat in flour and cut with doughnut cutter. Cook in hot grease, turning over once with fork. Drain in strainer and roll in sugar.
You may need more flour than just 5 cups for what your going to need on your counter to roll the dough. It is sticky until enough flour gets on dough. I don't use a doughnut cutter, I just use a drinking glass rim for the bigger doughnuts and a soda cap for the centers. My children use all kinds of cookie cutter to make their shapes. You can also use different things to roll them in or glaze them. If you'd want to put cream inside just don't cut out a center, then insert the cream in a hole you'd make. YUMMY