These are breadnuts:
[Sorry for the bad photo…it’s been rainy and cloudy for the past couple of days. Rainy season seems to have made a return appearance.]
The breadnut is related to, but different from, breadfruit. They are both somehow related to the mulberry. The short explanation is that a breadfruit is a large (fused) fruit with small seeds, and breadnuts are large seeds of a fused fruit.
Flavor wise, the breadnut is very mild. Not dissimilar to a chestnut, only less sweet. To prepare, I boiled for five minutes, then roasted for five in a 375 oven. They turned out fine. I could see using them in savory dishes (chestnut stuffing?), maybe browned in a saute dish and added as a starch to a meal.