An old recipe for monastic jelly - an unusual dessert with a historical flavor: this has been cooked in Rus' for centuries. It is served cold, if desired, berries and chopped fresh fruit can be added to it.
Pour oatmeal flakes with warm water and leave warm for a day.
Strain the resulting oatmeal through a sieve, separate and squeeze out the oatmeal.
Put the oatmeal solution on low heat and cook until thickened, about 15 minutes. No need to boil for a long time!
Stir butter into hot jelly, pour jelly into molds, cool. Serve with a glass of milk. If desired, you can sweeten the jelly.