Instructions

MAKE THE VANILLA SHORTBREAD WITH EGG YOLK:
Briony's secret ingredient: she added grated cooked egg yolk to make her biscuits shorter meaning more tender crumbly melt-in-mouth texture.
Hard-boil 2 eggs let cool peel and separate yolks.
Grate yolks on fine grater or mash with fork until crumbly.
In a bowl cream softened butter and powdered sugar until light and fluffy about 3 minutes.
Add grated egg yolks vanilla extract and almond extract if using. Mix until combined.
In a separate bowl whisk together flour cornstarch and salt.
Gradually add dry ingredients to butter mixture mixing on low speed until just combined.
Prue's goal: the shortbread should melt in the mouth and is beautifully crumbly.
Turn dough onto work surface and gently knead 2-3 times until it comes together don't overwork.
Divide dough in half flatten each into a disk wrap in plastic and refrigerate for 1 hour.

MAKE THE APPLE CIDER JAM:
Briony's Bristol tribute: she added apple cider jam instead of the more traditional raspberry jam to celebrate her home town of Bristol.
Pour apple cider into a wide heavy-bottomed saucepan.
Bring to a boil over high heat then reduce to medium-high and simmer vigorously until reduced by half about 20-25 minutes.
Add diced apples sugar lemon juice vinegar cinnamon and nutmeg.
Continue cooking stirring frequently until mixture thickens and reaches jam consistency about 30-40 minutes total.
Paul's description: that bite comes from the apple and cider ensure concentrated cider flavor.
If using pectin add during the last 5 minutes and boil hard for 1 minute.
Test doneness by placing a spoonful on a cold plate it should wrinkle when pushed.
Let cool completely.

ROLL AND CUT THE BISCUITS:
Preheat oven to 325°F. Line two baking sheets with parchment paper.
On a lightly floured surface roll out one portion of dough to 1/4-inch thickness.
Briony's elegant touch: use a fluted or scalloped round cutter about 2.5-3 inches for decorative edges.
Prue's praise: I certainly like the scalloped edges I think that looks beautiful.
Cut out rounds and place on prepared baking sheets spacing 1 inch apart.
Cut small circles about 1/2 inch in the center of half the rounds to create windows these will be the tops.
Paul's observation: they are pretty uniform in colour and size they're very neat.
Repeat with second portion of dough.
Refrigerate cut biscuits for 15 minutes before baking helps maintain shape.

BAKE:
Bake for 12-15 minutes until edges are very lightly golden.
Paul's assessment: uniform in colour watch carefully to avoid over-browning.
Let cool on baking sheets for 5 minutes then transfer to wire racks to cool completely.

MAKE THE ICING:
In a bowl whisk together powdered sugar apple cider or juice and vanilla extract until smooth.
The icing should be thick but pourable add more liquid or sugar as needed.
If desired divide and tint with food coloring.

MAKE THE CARAMELIZED APPLE TOPPING:
Slice apple as thinly as possible use a mandoline if available.
Heat butter in a skillet over medium heat.
Add apple slices in a single layer and sprinkle with sugar.
Cook until golden and caramelized on both sides about 2-3 minutes per side.
Paul's praise: combined with the caramelization on top the sweetness it just blows the mind.
Let cool on parchment paper.

ASSEMBLE THE EMPIRE BISCUITS:
Spread apple cider jam on the bottom solid biscuits about 1 tablespoon per biscuit.
Top with the biscuits that have holes cut in the center.
Spoon or pipe icing over the top biscuits allowing it to show through the center hole.
Before icing sets place a piece of caramelized apple on top of each biscuit.
Let icing set completely about 30 minutes.