In a medium pot, bring the coconut milk to a low simmer.
Whisk in the cinnamon and vanilla, breaking up any clumps from the cinnamon. (Add almond extract here too if using.)
Take a heat-proof spoon or small cup and while quickly whisking, slowly pour about a 1/4 cup of the hot milk into the eggs. Remember, pour S.L.O.W.L.Y. and whisk Q.U.I.C.K.L.Y.
Once you've whisked the hot milk into the egg, slowly pour the egg back into the simmering pot of coconut oil. This process slowly raises the temperature of the egg so that it incorporates into the milk without giving you scrambled eggs.
Once you've got the egg into the pot of milk, add the erythritol.
The add the blackberries and smash them with a potato masher or fork.
Remove from heat and cool the entire batter in the fridge.
Once completely cooled, transfer to your ice cream maker and proceed to manufacturer's directions for your machine.
Store in the freezer in a food-safe container until ready to enjoy!