Preheat the oven to 350 degrees. Put the squash in a bowl with 1 tablespoon of the olive oil. Toss well to coat, then transfer to a rimmed baking sheet. Roast the squash until tender, 20-30 minutes.
Heat the remaining tablespoon of olive oil in a saute pan over medium-low heat. Add the onion and saute until caramelized, 8-10 minutes. Add the mushrooms and saute until their liquid has evaporated, 8 - 10 minutes. Stir in the sage, salt, and squash and cook for about 2 minutes.
To serve, put 1 crepe in the center of a plate, spoon part of the vegetable mixture onto one side of the crepe, and fold the other side over the filling. Repeat with the remaining crepes and filling. Serve with a dollop of aioli and a scattering of chives.