Bake the kabocha squash and mash it.

Preheat the oven to 350 degrees F and lightly oil or butter an 8-inch round cake pan.

Place the dates in a bowl along with the baking soda and fill with boiling water. Allow dates to sit 10 to 15 minutes to soften. Strain the water and place dates in a high-powered blender.

Add the mashed kabocha squash, coconut oil, plain yogurt, and grated ginger to the blender. Blend until completely smooth. Add the two eggs and blend just until combined.

In a mixing bowl, whisk together the flour, coconut sugar, baking powder, cinnamon, allspice, and salt.

Pour the pureed kabocha mixture into the bowl with the dry mixture and stir together until combined. The batter will be thick.

Pour the cake batter into the prepared pan and smooth into an even layer using a rubber spatula or wooden spoon.

Place on the center rack of the oven and bake 35 to 45 minutes, until the center tests clean.

Allow cake to cool to room temperature, about 1 hour.

Heat the coconut milk, coconut sugar, cinnamon, allspice, and sea salt in a medium-sized skillet over medium-high heat and bring to a full boil. Reduce heat slightly and allow mixture to continue to cook at a gentle boil, whisking constantly, until dark brown and thickened, about 10 to 15 minutes. Remove from heat and add the butter and vanilla extract. Allow the caramel to cool.

Turn the cake out onto a cutting board or cake platter. Pour the chai caramel on the center of the cake and smooth it over the full surface of the cake. Sprinkle with chopped pistachios (or walnuts or pecans) and serve.