Generously butter a 7 inch springform pan. Cover the bottom of the pan with a crown of aluminum foil to prevent leakage.
Tear at least two cups of baguette into small pieces, into the bottom of the prepared pan. Make sure to cover the entire bottom and then some.
Pour the blueberries over the bread, spreading them out all over the pan.
In a small bowl, mix the rest of the mascarpone cheese with the remaining 1 Tablespoon vanilla. Drop in clumps all over the blueberries.
Put four eggs, 1 can coconut milk, ¼ cup mascarpone cheese, 1 Tablespoon vanilla, and the orange zest in a blender. Whir for at least two minutes. Pour over the pan, allowing the egg mixture to come almost up to the top of the pan.
Cover well with foil, and refrigerate for at least one hour, but preferably overnight.
Put one cup of water in the bottom of the Instant Pot. Put in a trivet.
Place the bread pudding on the trivet and lock on your lid. Make sure the toggle is set to sealing.
Set the Instant Pot for 35 minutes. Allow for a ten minute natural pressure release. Carefully take the pudding out of the pot and remove the foil. Check for doneness…if it is too runny, you can put it back in for 10 more minutes.
Serve warm or cold, with or without a blueberry sauce over it.