Millefeuille

Whisk flour and salt, add the cold water and melted butter, and mix with the scraper to a shaggy dough. Knead 60 seconds only, to rough smoothness, then press into a 2cm-thick square, score a shallow X across the top, wrap, and refrigerate 1 hour.

Look for A firm, slightly rough dough that holds its square; it should feel underworked, because it is.

Pound 200g butter between parchment to a 15cm square. Match its firmness to the rested dough: cool, pliable and matte, about 58-62°F for dairy butter. Chill 10 minutes if greasy; let it stand briefly if it cracks.

Look for The slab bends without cracking and leaves no oil on the parchment.

Roll the détrempe from the scored X into a 22cm square with the corners slightly thinner than the center. Set the butter square on it rotated 45 degrees, so it sits like a diamond in the square, and fold the four dough corners over to meet at the middle, sealing the seams with the heel of your hand. No butter showing.

Look for A sealed packet of even thickness with the block's edges faintly visible through the dough, like a letter in an envelope.

Roll the packet to 20 x 45cm, brush off excess flour, and fold in thirds. Turn 90 degrees. Repeat until five letter folds are complete, refrigerating 30 minutes after each fold. If the dough resists, rest it; if butter is brittle, give it a few minutes on the bench.

Look for A cool matte packet, with thin continuous layers visible at the edge.

Wrap the finished laminate and refrigerate at least 2 hours, better overnight. This rest relaxes the gluten so the sheet bakes flat instead of shrinking, and it is the make-ahead seam: the dough holds 3 days cold or a month frozen.

Look for Rested dough rolls out quiet and stays where you put it; underrested dough pulls back like elastic, and the oven will punish what the counter forgave.

The selected milk, vanilla pod, and seeds to a bare simmer in the saucepan, then off the heat, lid on, 15 minutes. Fish out the pod, pressing it dry against the side.

Look for Milk freckled through with seeds and smelling of vanilla before the lid goes on.

Whisk the yolks, sugar, and cornstarch in the bowl to a thick, pale, completely smooth paste.

Look for Pale lemon-colored and ribboning; no dry pockets of starch when you scrape the bottom.

Whisk a third of the hot milk into the yolk paste, then pour everything back into the saucepan. Cook over medium, whisking constantly and into the corners, up to a full boil, and hold it there 90 seconds.

Look for It thickens in a rush around 180°F, then big, slow bubbles burp through a cream that leaves the whisk's tracks standing.

Off the heat, beat in the cold butter and salt until glossy. Push the cream through the sieve into a shallow container, press film onto its surface, and refrigerate at least 2 hours.

Look for Cold, it mounds on a spoon and holds the mound: piping-stiff, not pourable.

Just before assembly, beat the cold cream smooth with the spatula, 30 seconds, and load the piping bag.

Look for Smooth and glossy again after its chill, holding a sharp point off the spatula.

Divide the chilled pastry equally. Roll each half to 22 x 32cm, about 3.5-4mm thick, on separate parchment sheets. Transfer to two half-sheet pans, dock every 2cm and refrigerate flat for 30 minutes. Heat the oven to 400°F.

Look for Two evenly thick sheets with straight relaxed edges.

Bake one sheet at a time under parchment and the third sheet pan for 25 minutes at 400°F. Remove the press and upper paper, then bake 8-12 minutes until deep gold and dry through. Repeat with the second sheet; keep it chilled until its turn.

Look for Flat as a board, deep gold edge to edge, and light for its size when the pan comes out.

Cool both sheets for 10 minutes. From each baked sheet, trim a usable 18 x 27cm rectangle and cut nine 6 x 9cm leaves, three across and three down. Use a sharp serrated knife with light short strokes and support the sheet flat. Save offcuts separately.

Look for Eighteen equal rectangles, with dry flaky centers and no bent or damp undersides.

Select six even leaves for the tops. Heat the oven to 450°F. Sift 2g icing sugar over each of those six and bake 3-5 minutes, watching until it melts amber. Cool completely on the rack; keep the twelve plain leaves aside.

Look for Six thin amber panes, glossy and free of black spots; twelve plain golden leaves.

Within 20 minutes of serving, pipe 60g cold custard on each of six plain leaves. Add a second plain leaf and another 60g custard, then one glazed top, caramel facing up. Use 720g custard in all; any piping allowance stays in the kitchen. Assemble six pastries.

Look for Level stacks with visible cream at the edges and crisp intact tops.