The custardy Canelé scaled to fill a full 24-mold tray. Same ratios, same method — just sized so you’re not left with two empty molds.

Ingredients

   
745g milk
85g heavy cream
100g butter
2 vanilla beans (or 16g vanilla extract)
375g granulated sugar
4g fleur de sel
2 whole eggs (~110g)
5 egg yolks (~90g)
88g aged rum
185g AP flour
33g cornstarch
  Nonstick spray (or beeswax) for molds

Steps

  1. In a pot, combine milk, cream, butter, and vanilla. Heat to 175°F — do not boil. Remove from heat. Let infuse 5 minutes.

  2. In a bowl, whisk sugar, salt, eggs, and yolks together.

  3. Slowly pour about ¼ of the hot milk into the egg mixture, whisking constantly to temper. Sift in flour and cornstarch together, whisk until smooth.

  4. Gradually add the remaining milk, whisking until fully combined. Stir in rum.

  5. Strain through a sieve. Refrigerate overnight (24 hours minimum).

  6. Coat 24 canelé molds with nonstick spray. Stir rested batter gently. Strain again if lumpy.

  7. Preheat oven to 525°F (550°F if baking a full tray — see notes). Fill each mold with ~75g of batter.

  8. Bake at 525°F for 11 minutes. Without opening the oven, drop to 400°F and continue baking for 50–55 minutes (see notes — a full tray browns slower, so it runs hotter than the single batch’s 375°F second stage).

  9. Unmold immediately onto a cooling rack upside down. Cool 2 hours. Eat the same day.

Analysis

Total batter weight: 1815g (excludes mold coating)

Component Amount %
Structure solids (flour + cornstarch) 218g 12.0%
Fat (butter, cream, milk, yolk) 179g 9.9%
Sugar (added + milk lactose) 414g 22.8%
Liquid (milk, cream, rum, egg water) 900g 49.6%
Egg/protein 53g 2.9%

Identical ratios to the single-batch Canelé — structure at ~12% keeps it in the custardy sweet spot (8–14%), just at 2.2× the volume. The extra yolk nudges fat and richness up a touch. Nothing about the larger batch changes the texture; only the oven’s heat recovery does, which is why a full tray wants the hotter start.

Notes

  • This is a straight scale-up of the custardy Canelé (~2.2×) sized to fill 24 molds at a full ~75g each. The ratios are unchanged, so it bakes identically.
  • Eggs are kept to whole counts (2 whole + 5 yolks); the rest scales to match their real weight. The extra yolk over a strict double makes it a hair richer — on-brand for the custardy version.
  • Oven load + start temp — don’t double-compensate. A full rack of cold molds craters the oven during the shock phase, so the effective temp at the molds runs well below the dial. There are two ways to fix that, and they’re alternatives, not a stack:
    • No steel, full tray: crank the dial to 550°F start to brute-force the effective temp back up to the ~525°F the batter wants. (Then drop to 400°F.)
    • With a steel (better): the steel restores the effective temp directly, so set the dial back to ~475–500°F start, not 550. Running 550 and a steel double-compensates and scorches the bottoms over a 60-min bake. Then drop to 375–400°F.
    • Either way, verify with a $10 oven thermometer (dials run 25–50°F off) — you want measured air near the high-shock target, then the lower second stage.
  • How low can the start go? Not below the high-shock regime. A steel lets you come down from 525 (small batches work at 450), because the steel still delivers a real shock — the exact high number is flexible. But you can’t bake low-only (350–375°F throughout): the dark lacquered crust is caramelization, which needs the surface at ~320–340°F, and a wet batter surface sits pinned at ~212°F until a hot oven dries it and drives it up. A 350–375°F oven never gets there — you’d get a pale, soft “blonde” canelé, no crust, and time can’t substitute for the missing heat. A steel delivers heat, it isn’t a temperature multiplier. So: steel + a real high shock (~475–525°F) → drop to 375–400°F. The 350–375 band is the second stage only, never the whole bake.
  • Mushrooming then collapsing flat usually means the shell didn’t set before the batter over-rose: don’t pull them early, keep the start hot, and don’t whisk air into the batter.
  • Big-batch browning: a full tray of cold molds is a big heat sink, so the oven runs effectively cooler and the canelés brown slower. Brown with heat, not time — run the second stage at 400°F (vs 375°F for the single batch) so they color within the normal ~55 min window. Chasing color by extending the bake at a lower temp just thickens the shell without adding much color. If they’re still pale, push the second stage to 410–415°F next time rather than adding minutes.
  • Non-convection (fanless) oven, full tray — the fixes, highest-impact first. A conventional home oven with 24 cold copper molds and no fan craters during the shock phase: the dial reads 525°F but the air around the molds drops 50–75°F the moment you load, and there’s no fan to push it back before the batter over-rises. That one fact drives the longer bakes, the drying, the mushrooming, and the uneven tops. In order:
    1. Preheat a baking steel — the single biggest fix. A ½″ steel on the lower-middle rack, preheated 45–60 min at the start temp; set the tray directly on it. Steel conducts ~10–20× faster than stone, so it dumps stored heat up into the cold molds exactly when recovery fails. Steel ≫ stone here. Buy one thing, buy this.
    2. Preheat hotter and longer + use an oven thermometer. 45–60 min so the walls and steel saturate (not just the air); start a full tray at 550°F. A $10 thermometer tells you whether your 550 is really 510 — dials run 25–50°F off.
    3. Stop opening the oven to push the mushrooms down. Every open dumps the heat you can’t recover and causes the next mushroom. The mushroom self-settles as the shell sets and the crumb contracts — opening is a symptom of under-temp, not a fix. Door shut through the whole shock stage.
    4. Batter levers: fill a consistent ~75g (overfill erupts); batter goes in cold from the fridge (sets its shell before it can over-rise); stir, don’t whisk (whisked-in air mushrooms).
    5. Rotate once, late. Fanless ovens have hot corners — rotate 180° once, ~halfway, but only after the shell sets (~20+ min); open fast, turn, close. For even tops, not rescue.
    6. Drying = hotter-shorter, not cooler-longer. Pull at color (deep mahogany), not the clock.
    7. Honest fallback: bake 12 at a time. If it still craters after all of the above, half the heat sink = twice the recovery = a clean rise. The batter keeps 4–5 days, so splitting is a legitimate fix, not a failure. (Lower-structure batters set more slowly and punish a slow oven harder, so get the tray reliable at 12% structure first before dropping it.)
  • Nonstick spray works fine — no beeswax needed.
  • Same flavor variations apply: matcha/hojicha (12g per ~500g batter), coffee (instant espresso paste).
  • Batter keeps 4–5 days refrigerated; bake in trays as needed rather than all at once.