Day 1: Make the Dough - Steps 1 through 4 of my Brioche recipe. But instead of refrigerating for the minimum 2 hours, let's refrigerate it overnight.

Day 2: Shaping - Remove the dough from the refrigerator and lightly punch it down. Press the cold dough into a greased 8- or 9-inch springform pan, smoothing it out evenly. Cover the pan with a damp towel and plastic wrap. Let rise in a warm place until puffed, about 1 - 1 ½ hours. Preheat the oven to 356°F. Place a parchment-lined baking tray under the pan to catch drippings.

Day 2: Make the Topping and Bake - In a small saucepan, melt the butter over medium heat. Stir in honey, sugar, vanilla paste, and salt. Simmer briefly. Stir in the sliced almonds. Remove from heat, stir in the vanilla and almond extracts, then set aside until ready to spread on the dough. Let the topping cool slightly (~5 minutes) before spreading—this ensures it spreads evenly without sinking into the dough. Once the dough is done rising, spread the prepared topping over the dough. Bake for 21–25 minutes, until the internal temperature reaches 188-190°F and the top is golden brown. Run a knife around the edges immediately after baking to prevent sticking. Let cool for 20 minutes in the pan, then carefully remove and cool completely on a wire rack. This will take at least 1 ½ hours.

Make the Pastry Cream Filling - In a medium saucepan, heat ¾ cup milk, 2 tablespoons sugar, vanilla paste, and salt until just simmering. In a bowl, whisk the remaining ¼ cup milk with cornstarch, the remaining sugar, and egg yolks until smooth and lightened. Slowly whisk half of the hot milk into the yolk mixture, then return to the saucepan. Cook, whisking constantly, until thickened. Remove from heat, add butter and vanilla extract, and strain through a fine-mesh sieve. Cover with plastic wrap directly on the surface and refrigerate until cool. Bloom gelatin in water, then melt in the microwave. Whip the heavy cream and powdered sugar in a stand mixer, gradually incorporating the melted gelatin, until stiff peaks form. Beat the chilled pastry cream until smooth, then fold in ⅓ of the whipped cream to lighten in. Then gently fold in the rest of the whipped cream, folding very gently until incorporated.

Assembly - Slice the cake horizontally. Spread the filling onto the bottom layer, then place the top layer over it. Chill the assembled cake in the refrigerator for at least 1 hour before serving.