Lightly grease 4 (6-ounce) heat-safe ramekins with coconut oil.
In a large mixing bowl, whisk together the eggs, almond milk, melted coconut oil, and vanilla extract until combined.
Into the wet ingredients, sift the almond flour, monk fruit powder, cacao powder, cream of tartar, baking soda, and arrowroot powder. Whisk just until a smooth batter forms.
Stir in the chocolate chips.
Divide the mixture evenly among the 4 ramekins, f illing them until ¾ full. Pour the water into the Instant Pot bowl and set a steamer rack or trivet in the bottom. Place three ramekins on the rack, and one on top of the three, in the center.
Secure the lid on the Instant Pot and move the vent knob to the sealed position.
Select “Manual” and cook on high pressure for 10 minutes.
Once the cooking time is up, carefully move the knob to “Venting” to quickly release the pressure.
The ramekins will be hot and slippery, so wear oven mitts to remove them from the Instant Pot.
(Don’t be concerned if there is a little extra liquid around the ramekin rims when you open the Instant Pot. It will absorb into the cakes in a minute or two.) Serve immediately in ramekins or scooped onto plates while still warm and molten.