Boston cream pie layer cake

Combine the eggs, sugar and salt in the mixer bowl; whisk by hand over a saucepan of just-under-boiling water to about 113F.

Whip with the whisk attachment, medium rising to high, about 5 minutes, to a thick ribbon that takes several seconds to disappear; the oven is at 350 with a rack in the center.

Off the mixer, sift the flour over in stages and fold gently with a skimmer.

Before the last flour disappears, stream in half the melted butter and fold; add the rest of the butter and the vanilla extract and fold quickly.

Divide between the two ungreased 9-inch pans, pop large bubbles and tap.

Bake at 350 side by side until golden and puffed, a tester comes out clean and the cakes pull away a little from the sides.

Heat the milk with the vanilla paste to a bare simmer.

Sprinkle the gelatin evenly over the cold water and leave at least 10 minutes to soften.

Combine salt, sugar and cornstarch; add the yolks and whisk slowly, then vigorously until very pale and ribboning. Do not let the mixture sit or hard bits of yolk form.

Off the heat, slowly whisk the hot milk into the yolk mixture in stages; return everything to the saucepan.

Cool the cakes upside down on a rack so the steam escapes without the delicate crumb collapsing.

Cook over medium heat until it comes to a boil, which the cornstarch needs to thicken.

Off the heat, add the gelatin while hot but not boiling, then the cubed butter.

Strain while hot into a clean bowl; press plastic onto the surface and chill to set (can be made several days ahead).

Unmold the ungreased cakes with an offset spatula and fingertips, peeling off the bottom film and the brown top layer.

Split each layer horizontally with a serrated knife: saw at eye level, rotate the cake keeping a hand flat on top, then cut through with short rapid strokes.

Stir the set pastry cream smooth; whip the heavy cream to between medium and firm peaks.

Make a soak of milk, demerara sugar, a pinch of salt and vanilla extract.

Fold the whipped cream into the pastry cream in two additions until light and glossy.

Line a 9-inch pan with plastic overhang; lay the best layer in first (it becomes the top), dab with soak, spread a heaping cup of filling to the edges; put any broken layers in the middle.

Repeat soak and filling; soak the final layer before placing it soaked side down.

Pat down, pull the plastic up over the top to align the layers, and chill at least an hour until the gelatin sets.

Warm the heavy cream to just below a simmer; add corn syrup and salt; pour with the butter over the chocolate and let it sit a few minutes to melt.

Invert the cake onto a trimmed cake round on a wire rack set in a baking sheet; peel off the plastic and smooth any filling peeking out with an offset spatula.

Stir the glaze with vanilla extract; once thickened pour from the center, letting it cascade down the sides in natural drips, and help it over bare spots.

Chill until the glaze sets; gelatin needs about four hours to set, ideally overnight, before slicing with a serrated knife.