Heat the milk and 150g golden caster sugar for 3-4 minutes in a saucepan until hand hot. Scrape the seeds from the vanilla bean into the milk, then add the pod. Cover, remove from the heat and leave to infuse for one hour.
Pour the cream into a medium bowl and set a strainer over it. Fit the bowl into a bigger bowl filled with ice. In another bowl, stir together the egg yolks. Gently rewarm the milk, then gradually pour some of the milk into the yolks, whisking as you pour. Scrape the contents of the bowl back into the saucepan.
Cook over a low heat, stirring constantly and scraping the bottom with a rubber spatula, for 5-7 minutes until the custard thickens enough to coat the spatula. Strain the custard into the heavy cream and stir continuously until it cools. Remove the bowl filled with the ice cream mixture and transfer to the fridge. Leave to chill for at least 4-5 hours, preferably overnight.
Add the dried fruit, orange juice and remaining golden caster sugar to a small saucepan. Stir together, then bring to the boil. Reduce the heat and leave to simmer for 5 minutes until the fruit is plump and syrupy. Set aside to cool.
Once the ice cream mixture is cool, add to an ice cream maker and churn according to machine instructions, adding the fruit in the last 5 minutes. Pour into a large freezer-safe container and leave to set for 4-5 hours, or overnight.
Whisk 3 egg whites with a handheld mixer until soft peaks appear. Gradually add the white caster sugar bit by bit, whisking well after each addition. Once the mixture is thick and voluminous, divide into 2 bowls. Add the cocoa powder to one of the bowls and beat briefly until combined.
Preheat the oven to 170°C/150°C fan/gas mark 4. On a piece of greaseproof paper, draw on bunny ears measuring 17cm x 8cm. Turn the template over and use a little meringue to stick each corner to a large baking tray. Pipe the plain meringue around the outside of the ear shape using a 1cm nozzle, then fill the inside of the ear with the chocolate meringue mixture. Transfer to the oven and immediately reduce the heat to 160°C/140°C fan/gas mark 3. Bake for 45 minutes, then turn the oven off. Leave the ears in the oven until it’s cold, preferably overnight.
Preheat the oven to 200°C/180°C fan/gas mark 6. Chop the hot cross buns into 2-3 cm squares and toss in the melted butter, followed by the demerara sugar. Spread out on a baking tray and bake for 10-12 minutes until the croutons are browned and toasty, giving the tray a shake halfway through. Set aside to cool.
In a trifle bowl, add a few scoops of ice cream, a scattering of the croutons, a good drizzle of the chocolate sauce and a few squirts of whipped cream. Continue to build your sundae in this way, finishing with a final drizzle of chocolate sauce, the last of the croutons and the crushed micro eggs. Carefully push in the bunny ears and eat immediately.