Step 1

For pastry, beat butter, icing sugar and vanilla in an electric mixer fitted with the paddle attachment until smooth. Fold through almond meal and a pinch of salt. Add egg and mix until just combined, then gradually add flour, being careful not to overmix. Bring together into a ball, wrap in plastic wrap and refrigerate for 1 hour to rest.

Step 2

For caramel filling, scatter sugar evenly in a saucepan over high heat. Cook, swirling pan, until dark caramel (3-5 minutes), then carefully stir in glucose. Meanwhile, bring cream to a simmer in a saucepan over medium heat. Pour cream into caramel (be careful; hot caramel will spit) and stir occasionally until it reaches 106°C on a sugar thermometer. Remove from heat and cool until about 50°C. Soften gelatine in a bowl of cold water (5 minutes), then squeeze water from gelatine, add to pan, and blend in with a hand-held blender, or beat in vigorously. Add butter and blend again until smooth. Spoon into a piping bag without a nozzle and cool.

Step 3

Meanwhile, roll out pastry between 2 sheets of baking paper to 4mm-thick and line a 26cm-diameter loose-bottomed fluted tart tin. Trim edges then refrigerate to rest (2 hours).

Step 4

Preheat oven to 160°C. Blind-bake tart until golden (20-25 minutes). Remove paper and weights and bake until base is set and cooked through (5-10 minutes). Cool tart (in tin) on a wire rack, then pipe caramel into base and chill to firm up (30 minutes).

Step 5

For dark chocolate ganache, place chocolate in a heat-proof bowl. Bring cream and glucose to the boil in a saucepan, pur cream over chocolate, stand for 10 seconds, then stir to melt and combine. Stir in cold butter until smooth, being careful not to overmix, then cool to room temperature. Spread chocolate ganache over caramel and chill to cool and set (2 hours). Sprinkle tart with salt flakes to serve. Tart is best eaten on the day of making but will keep refrigerated in an airtight container for 2 days.