Bake the potatoes until fork tender. Blanch and shock the broccoli and process in the food processor, removing the larger part of the stem. Run the potatoes through a food mill or ricer. Do not mash. Mix the potatoes with the broccoli and some salt and slowly incorporate the flour. Start with 2 cups and mix well. If it isn't dry enough start adding more as needed. This part is hard to explain because it is really about the feeling of the dough and knowing when it is ready comes with practice and experience. Finally roll out the dough and cut your gnocchi, then roll them out on a gnocchi board or fork.

To make the sauce, saute a small amount of onion in 1 tablespoon of butter. When it looks like it's just about to brown, whisk in 1 tablespoon of flour. Next add 1 ¾ cups of milk and whisk well. Bring to a simmer to thicken, then turn to low and let it cool about 5 minutes. Finally whisk in 8 oz of shredded sharp cheddar.

Boil off the gnocchi in 2 separate batches, and add right to the sauce. Keep them in the sauce over very low heat until ready to serve.