Khanom Chan (ขนมชั้น)

The Cake You Peel Apart

ขนมชั้น — "layered sweet" — is built the slow way: batter poured a few millimetres deep, steamed until it sets, then the next layer poured on top, over and over until the tray is full. That is the whole point of the cake: each layer stays separate, and the finished block peels apart in thin, translucent sheets that pull cleanly off the layer below — Pim's ครัวบ้านพิม tested her formula through half a dozen batches to get exactly that behaviour.

The texture comes from the flour trio. Kapook's recipe mixes rice flour, tapioca starch and arrowroot flour and kneads the blend into sweetened coconut milk by hand for fifteen minutes — the kneading is what gives the cake its spring. Pim kneads thirty to forty minutes and is blunt about the rule: the longer you knead, the softer the cake. Aroifin's selling batch is gentler, five minutes, because its batter is looser.

Layers count. Aroifin records the auspicious rule: drop nine layers for the lucky number nine — the number for housewarmings and promotions. Kapook builds nine to ten, alternating white and green; Wongnai's three-tone version grades its pandan from white through light to dark green. The colour itself is negotiable — Pim admits her shortcut is plain green food colouring — but the layer discipline is not.

The Recipe (home version, from Kapook — Rin Silpachai)

The selling ratio (TrueID, per tray): 25 g rice flour, 145 g tapioca starch, 55 g arrowroot flour, 280 g sugar, ¼ tsp salt, 650–750 g coconut cream and thin coconut milk, 50 g concentrated pandan juice (15 leaves blended with 1 cup of water, strained to ½ cup). The condensed-milk build (Wongnai): 276 g tapioca starch, 62 g rice flour, 30 g arrowroot, 30 g mung bean flour, 1,200 ml coconut milk, 100 g sweetened condensed milk, 200 g sugar, 300 ml pandan juice.

The Method

1. The sweet coconut. Stir the sugar and coconut milk in a pot over medium heat about 5 minutes until the sugar dissolves — do not let it boil — then lift off and cool.
2. The hot tray. Pre-steam the empty tray in the boiling steamer about 15 minutes. A hot tray releases the cake later; Wongnai's alternative is oiling, but pre-steaming is the cleaner trick.
3. The knead. Mix the rice flour, tapioca starch and arrowroot flour, gradually pour in the coconut mixture and knead by hand about 15 minutes until the dough is one smooth mass. Strain through a sieve so no flour grains survive.
4. The two batters. Divide into two bowls: one mixed with the pandan juice, one with the jasmine water.
5. Layer by layer. Pour about ⅓ cup per layer — white first — and steam covered 5 minutes, then green 5 minutes, alternating until the batter is gone, about 9–10 layers. The last layer gets 7 minutes. Stir the batter before every pour; the starch settles.
6. The rest and the cut. Rest until completely cool, about 3 hours, then lift out of the tray. Dip the knife in hot water and press-cut — never saw — into diamonds or squares.

Where Thai Sources Disagree

How Western Versions Get It Wrong

• Baking it. Khanom chan is steamed, never baked. An oven dries the batter into a cake; only steam keeps the layers translucent and peelable.
• One thick pour. The whole identity of the dish is the separate layers. Pouring the batter in one or two thick slabs produces a coconut pudding, not ขนมชั้น.
• Skipping the knead. Whisking the flours together is not kneading. The hand-kneaded dough is what gives the layers their spring; under-kneaded batter bakes into a stiff, grainy sheet.
• Cutting warm. The cake must rest until completely cold — Kapook says about three hours — or the layers smear and the knife drags. The hot-knife press-cut only works on a cold cake.
• Pandan essence as a substitute for the real thing. Concentrated pandan juice carries both colour and fragrance; a few drops of essence colour nothing. The Thai shortcut is food colouring, which at least is honest about being colour-only.

UK Ingredient Notes

• Rice flour and tapioca starch: standard in UK supermarkets' free-from sections and every Asian grocer.
• Arrowroot flour (แป้งเท้ายายม่อม): at Thai grocers; cornstarch is the accepted substitute per Pim's recipe.
• Coconut milk: use full-fat tinned; a good brand separates into cream and thin milk, which the TrueID ratio uses as two ingredients.
• Pandan leaves: frozen at Thai and East Asian grocers — blend 15 leaves with a cup of water and strain for the concentrated juice. Pandan essence from Thai grocers is the fallback for fragrance only.
• Jasmine-scented water: steep a few drops of jasmine essence in water, or use plain water — the white layer loses fragrance, not structure.

Sources

This recipe is translated from the following Thai-language sources. Where they disagree, we've said so.