Use of pastry to cement the top of a dutch oven or casserole when baking a stew or pot roast, typically of meats. Create a simple mixture of flour and water and press it all around the edges where the pot and lid meet to create a seal. Wash the luting paste with a mixture of the white of one egg with 2 tablespoons of water, this will give it a nice golden sheen for presentation. Luting will keep the liquid inside the pot increasing moistness of the food and makes for a dramatic presentation when you crack it off the pot before serving.
Luting is commonly done with Baeckoffe, an Alsatian oven baked stew. A band of heavy aluminum foil can be used as well.