Spray inside bottom and sides of oven safe bowl with non-stick spray. Set aside.
In another large bowl, whisk eggs, milk, syrup, cinnamon and vanilla together.
Remove 3-4 slices of bread from full loaf (these won't be used). Chop up remaining slices of bread into 1" cubes.
Add bread into eggs and mix together. Coat the egg mixture with the bread until absorbed.
Pour half of bread mixture into prepared greased bowl. Sprinkle half of raisins on top. Add remaining bread mixture and sprinkle raisins on top. Cover bowl with foil.
Add 1 cup of water into Instant Pot.
If using foil sling method, place trivet in bottom of Instant Pot. Then place foil sling on top trivet with handles coming up to the rim on both sides. Place bowl on sling.
If using the silicone sling method, place foil covered bowl on silicone sling base and using the handles, lower down into the Instant Pot.
Close lid and turn knob to sealing position. Pressure cook on high for 30 minutes. Allow 10 minute natural pressure release. Manually release any remaining pressure.
Serve with maple syrup drizzled or warm apple sauce on top.