Preheat the oven to 180°C.
Melt the sugar in a small ovenproof frying pan over low heat.
Add the butter and heat until the mixture reaches a caramel colour.
Add the apricot halves cut-side up and scatter with sultanas.
Cook gently for 2 to 3 minutes until the apricots soften.
Roll out the pastry on a floured surface to roughly 3mm thickness.
Cut a pastry circle the size of the frying pan and place it over the apricots.
Bake in the oven for 12 to 15 minutes until the pastry is golden-brown.
Cool slightly and turn the tart out onto a serving plate using a palette knife.
Melt additional sugar in a non-stick pan until it turns to caramel.
Stir in the almonds until coated and pour onto a non-stick mat to cool.
Break the cooled brittle into pieces.
Serve tart wedges with ice cream and a sprinkle of almond brittle.