Baking from Frozen:
Defrost croissants overnight in the fridge.
Place croissants on a tray lined with parchment paper, with 2” of space around each croissant. Place the tray of croissants on the top rack of a cold oven. Put a pan of boiling water on the bottom rack of the oven under the croissants. Let croissants rise for an hour or until jiggly.
Once croissants are proofed, take them and the pan of water out and preheat the oven to 350℉. Brush croissants with an egg wash.
Once the oven is preheated, bake on the middle rack for 15-18 minutes or until golden brown.