Make the gnocchi: Poke the butternut squash with a fork all around and roast at 350F for about 1 1/2 hours until you can stick a fork through the neck pretty easily.
Cool, cut in half, then scoop out and discard the seeds. Next, scoop out the flesh into a medium bowl and discard the skin. You’ll only need half of the squash so you can eat the rest separately.
Add the olive oil and salt and mix them in, then add the gram and tapioca flours, mixing in 1/2 cup at a time. It will come together into a sticky dough ball. Knead it a few times to make sure it’s uniformly mixed (no chunks of flour or squash). If the dough really sticks to your fingers, add a little bit more flour, but not too much.
Break off spoonfuls of dough and roll them in your floured hands into gnocchi-sized ellipses or cylinders, about 1" long. You can optionally slide them over the back of a fork or spoon to make little patterns if you like. Place the gnocchi on a parchment-lined baking sheet – freeze until you're ready to cook them.
Make the sauce: Heat the olive oil in a large pan over medium-high heat, then add the garlic and sage (oregano works nicely here too). Cook for 2-3 minutes until golden but not too brown, then add the crushed tomatoes.
Turn the heat down to let the sauce bubble and simmer while the gnocchi cook, then taste for salt and pepper and adjust as needed.
Cook and serve: Drop the gnocchi into a large pot of salted, boiling water. They will pop up to the top after a few minutes. After about 10 minutes of boiling, take a large one out and taste it or cut it in half to see if it’s still doughy in the middle. If they’re frozen, they will take longer to cook (up to 20 minutes or so, depending on how big they are).
Once they’re cooked through, drain the water, toss the gnocchi with the sauce, and serve up yummy plates. Top with vegan parmesan and freshly ground pepper if you like.