Reheat Croissants in an Air Fryer

Doneness

Surface is a glossy amber-gold colour matching the original bakery finish (NOT a deep mahogany — that's the burnt-butter line crossed). The lamination crescent-pattern is visibly re-puffed; pressed gently between two fingers the layers separate audibly with the signature croissant shatter-sound (this is the doneness cue — a stale croissant compresses silently). The interior visible at any pulled-apart layer should show the open honeycomb crumb characteristic of a fresh croissant (the layered air pockets re-expand under the steam from the surface mist). Hold a croissant by one end and the other end should hold its shape rather than drooping. Picked up the croissant should feel light in the hand (not weighty-dense like a stale one).

Technique

Pull croissants from the fridge or counter — room-temperature works equally well. Load whole, single-layer, with at least ½-inch gaps between each so the convection wraps every face. No oil. Mist the OUTSIDE of each croissant ONCE with a fine spray of water from a clean kitchen spray bottle — the surface mist re-supplies the moisture that flaky-layer pastry loses overnight, and the convection air at 300 °F turns that mist into the steam that re-puffs the lamination. Skip the inside; misting the interior makes the layered crumb gummy. Cook 3 minutes at 300 °F — the low-and-slow profile that revives the shatter-crisp layers without scorching the surface butter. The butter in the laminated dough has a smoke point near 350 °F as melted-clarified, but the surface butter on a croissant is past the milk-solids stage from the original bake and burns much faster than fresh butter; 320 °F is the threshold above which the surface goes from glossy-amber to bitter-dark in under 60 seconds. Frozen-bakery-croissant variants (Trader Joe's Mini Croissants, Williams Sonoma frozen, Costco Kirkland frozen 8-pack) start from frozen at 300 °F / 4 min 30 sec — the extra 90 seconds is for the freezer-cold centre to warm through; the surface mist still applies.

Watch out for

• !Do NOT exceed 310 °F. The butter on the surface of a croissant has been through one bake already and the milk solids have started to brown — the second bake at high heat takes those milk solids from amber-glossy to bitter-dark scorched in a 60-90 second window above 320 °F. The 300 °F mark is the sweet spot; 310 °F is the absolute ceiling. Higher temperatures don't reheat the croissant faster — they just burn the surface butter while the interior remains cold.
• !Light water mist on the outside only — never inside. The single-pump surface mist (about ⅛ teaspoon of water per croissant) provides the steam that re-puffs the lamination; misting the cut interior of a croissant (or worse, dipping it in water) saturates the layered crumb and produces a gummy doughy texture instead of the shatter-crisp finish. Mist the outside, not the inside.
• !Single layer with ½-inch gaps non-negotiable. Croissants are large-volume / low-density pastry and overlapping pieces block the convection airflow that re-puffs the layers; touching croissants stay flat-and-soft on their contact faces. A 5-qt basket fits 2-3 standard bakery croissants single-layer; a 4-qt basket fits 1-2. Cook 2 batches rather than crowding — each batch is only 3 minutes so total under 8 minutes for 6 croissants.
• !Frozen bakery-croissant variants (Trader Joe's frozen Mini Croissants, Williams Sonoma frozen) need +90 sec at the same 300 °F temperature — start from frozen, no thaw, surface mist on the freezer-frosted croissant before load (the freezer ice IS the mist for the first 60 sec; add an extra spray if the croissant has been freezer-stored over a month and surface ice has sublimated). Total 4 min 30 sec at 300 °F. Filled-croissant variants (almond, chocolate-pain-au-chocolat, ham-and-cheese) work in the same profile but check at 3 min — the filling holds heat and over-cooking dries the wrap.