Preheat the oven to 375 degrees and grease an 8-inch pan with coconut oil.
In a medium bowl, combine the flour, cinnamon, baking powder, allspice, and salt; set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat together the tahini, honey, coconut oil, and vanilla extract at medium-low speed until smooth. Add the egg and lemon zest and beat until combined.
Add in half of the almond milk and mix at low speed until combined, then fold in half of the flour mixture and mix until nearly combined. Repeat again until a thick dough forms.
Pour the dough into the cake pan and smooth it over with a spatula. Place the pan in the oven and bake until a toothpick inserted into the center comes out clean, about 40 to 45 minutes
Remove from the oven and place on a wire rack to cool.
To serve, dust with the powdered sugar.