Mix the powdered glucose, sugar and stabiliser, then add the egg yolks. Heat the milk and cream, then add the first mixture. Cook the whole mixture at 83-85°C (181-185°F), like a crème anglaise. Let it cool briefy, then add the halved and scraped vanilla pods. Combine, then let it infuse for 2 hours. Remove and rinse the pods.
Whisk the egg yolks and sugar (1) together. Then whip the egg whites and stiffen them with the sugar (2). Gently pour the sifted flour over the egg yolk + sugar mixture, mixing with a spatula. Incorporate the whipped egg whites in two batches. (Do not stop whipping the egg whites before using them.) Spread out a very thin layer of the dough on a Silpat® mat and bake for 5-6 minutes at 185°C (365°F). Cover with cellophane paper straight after removing from the oven.
Cook a syrup with the sugars and water. At 110°C (230°F), start beating the egg whites. At 120°C (248°F), pour the syrup over the whipped egg whites. Let it beat for 20 minutes. Dispense the meringue using a pastry bag with a plain tip.
Boil the water and sugar, then add the pods used previously in the ice cream. Allow it to infuse.
Melt the fondant and glucose in a saucepan. Cook it all together at 159°C (318°F) (the mass must not change colour). Pour the mass onto a Silpat® mat to cool it down completely. Mix the paste, then spread out the powder obtained using a little sieve on a Silpat® mat. Cut out 11 cm circles using a cookie cutter. Melt the powder in the oven at 180°C (356°F) for 2 to 4 minutes. Let it cool, then peel off the opaline.
Arrange the biscuit in a 35x35 cm tin, 1 cm high. Soak the biscuit with the vanilla syrup. Churn the ice cream, then spread it out over the biscuit, level with the top of the tin. Place the tin in the freezer. Start the meringue. Once the ice cream has set, cut it out into a 9 cm diameter circle. Place the ice cream disc on the plate, then coat it with Italian meringue using a pastry bag. Smoothen the meringue using an angled spatula. Burn the meringue with a blowtorch. Lightly sprinkle the meringue with fleur de sel, then place the opaline. Finish the assembly with a sprinkle of vanilla powder obtained by drying the pods used in the syrup.