One option would be to buy a jar of pumpkin or squash baby food, which would be closer to the quantity called for in the recipe than a full can.
I'm pretty sure you could substitute 1/4 cup of mashed ripe banana, but that would significantly change the texture.
You could buy frozen winter squash (Bird's Eye has a butternut squash), thaw out some cubes, puree them, and use 1/4 cup of that. Basically any winter squash can be swapped in for pumpkin puree (and in fact I've heard rumors that the canned pumpkin is in fact some other variety of squash, which is one of a number of reasons that pumpkin pie made from an actual pie pumpkin rarely turns out as well as pumpkin pie made with canned pumpkin from Libby's.)
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I'm pretty sure you could substitute 1/4 cup of mashed ripe banana, but that would significantly change the texture.
You could buy frozen winter squash (Bird's Eye has a butternut squash), thaw out some cubes, puree them, and use 1/4 cup of that. Basically any winter squash can be swapped in for pumpkin puree (and in fact I've heard rumors that the canned pumpkin is in fact some other variety of squash, which is one of a number of reasons that pumpkin pie made from an actual pie pumpkin rarely turns out as well as pumpkin pie made with canned pumpkin from Libby's.)