Tofu can't be easily substituted. If you're concerned about flavor, the soy flavor is not noticeable with the right ingredients. My partner doesn't like tofu but this tart is his favorite dessert from my blog! And when I had a cake business, body-building omnivores wouldn't believe me when I said that tofu is in this tart! The chocolate can be combined with coconut cream and milk to make a chocolate ganache filling. However, I haven't tested quantities so can't vouch for results. Alternatively, check out my chocolate avocado mousse tart.