Place the dates and bicarbonate of soda in a heatproof bowl and add the boiling water. Let stand for 20 minutes or until softened.
Set up your Q for indirect cooking with the trivet and convection tray in place. Preheat on high for 10 minutes.
Beat the butter, sugar, and vanilla, with an electric mixer, until pale and creamy. Add the eggs, one at a time, and beat well after each one. Using a large spoon, stir in the flour and date mixture. Mix thoroughly.
Once the Q is preheated, turn to the roast setting. Pour the pudding into the casserole dish and place on the trivet. Cook for 35 to 40 minutes or until a skewer comes out clean when inserted into the centre of the pudding.
Remove the casserole dish from the Q and turn out the pudding onto a wire rack.
Return the casserole dish to the Q and preheat for 2 to 3 minutes. Add the brown sugar, cream, and butter to the casserole dish and cook, stirring, until the sugar and butter have dissolved. Once the sauce has begun to boil, close the lid and simmer for 3 minutes, lifting the lid to stir every minute.
Remove the sauce from the Q, pour into a jug and serve with slices of the warm sticky date pudding.