Place the apples, spices, water and orange slices (if using) in an Instant Pot.
Close the pressure cooker lid, set the valve to the "seal" position, and cook on high pressure for 30 minutes.
After 30 minutes, slowly turn the pressure release valve to begin venting pressurized steam. Once the valve has finished releasing steam, twist and turn the lid open.
Use a fine mesh strainer or cheesecloth to separate the liquid from the apples, orange slices and spices.
Taste and check the sweetness. If you'd like it to be a little sweeter, add 1 tablespoon of coconut sugar or maple syrup. Taste again and add more if needed.
Optional Step: Blend with butter if desired. After straining out the apples spices I usually pour the apple cider back in the Instant Pot, add the butter, and blend with an immersion blender, but you could pour the cider and butter into a traditional blender and mix it up that way, too.
Serve warm with cinnamon sticks, star anise, or fresh cranberries for garnish if desired.