1. Prepare the Dulcey Dome:

1. Soften gelatin in cold water.
2. Melt Dulcey chocolate in the microwave in short intervals, stirring until smooth.
3. Heat milk in a saucepan until just below boiling. Stir in softened gelatin until dissolved.
4. Pour over melted chocolate and mix until smooth.
5. Whip heavy cream to soft peaks and fold into the chocolate mixture.
6. Pour into dome molds and freeze until firm.

2. Prepare the Pastry Crust:

1. Beat butter and icing sugar until light and fluffy.
2. Mix in gluten-free flour, hazelnut powder, and salt until combined.
3. Add egg and mix until a dough forms.
4. Wrap dough in plastic wrap and refrigerate for 30 minutes.
5. Roll out, fit into a tart pan, and bake at 350°F (175°C) for 15-20 minutes until golden. Let cool.

3. Prepare the Hazelnut Cream:

1. Combine butter, icing sugar, hazelnut powder, and egg until smooth.
2. Spread into the cooled tart crust and bake at 350°F (175°C) for 10-15 minutes until set. Cool completely.

4. Prepare the Fondant Apples:

1. Sauté apple slices in a pan over medium heat until tender but not mushy.
2. Layer cooked apples neatly over the hazelnut cream in the tart.

5. Prepare the Creamy Caramel:

1. Heat caster sugar in a saucepan over medium heat until melted and amber in color.
2. Stir in heavy cream and butter carefully until smooth.
3. Remove from heat and mix in hazelnut praline paste. Let cool slightly.
4. Drizzle caramel over the apple layer in the tart.

6. Prepare the Frosting:

1. Soften gelatin powder in cold water.
2. Heat water, sugar, and glucose syrup in a saucepan until boiling.
3. Stir in heavy cream and melted Dulcey chocolate.
4. Add softened gelatin and mix until fully dissolved.
5. Allow frosting to cool slightly before pouring over frozen Dulcey domes for a glossy finish.

7. Assemble the Tart:

1. Carefully position glazed Dulcey domes on top of the caramel layer in the tart.
2. Garnish with chopped hazelnuts or edible gold leaf for an elegant touch.
3. Let tart sit at room temperature for 10-15 minutes before slicing and serving.