Slice butternut squash in half, then peel off skin. Dice into 1-inch pieces, then cook for 12-15 min in a large pot of water. Drain water from squash, then blend in the Vitamix. Reserve 1 cup puree, and save the rest for later - it freezes well!
Mix together squash puree, nutmeg, salt and pepper, parmesan cheese, egg and 1/3 cup of the flour. Keep adding flour in third cup measurements, mixing together with your hands as necessary. It should feel like a soft dough.
Meanwhile, heat 1 tbsp olive oil in a large skillet. Add onions, then cook on med-low heat for 10-15 min.
On a floured surface, break dough into four equal parts. Stretch and roll out each ball into thick ropes of dough, breaking in half and continuing to roll and thin out to 1-inch round ropes.
Meanwhile, add mushrooms and garlic to the skillet of onions and cook for 5-7 min until all juices release.
Arrange all ropes of dough in a row then slice into 1-inch thick pieces of gnocchi using a pizza cutter or knife. Cook gnocchi in a large pot of boiling salted water for 2-3 min. Gnocchi should be floating when finished cooking.
Drain then add to skillet along with kale and butter, cooking for 2-3 min. Stir in chopped sage then remove from heat.
Serve with grated parmesan cheese and enjoy! Gnocchi freezes well on its own up to three months and can be made ahead of time too!