Let milk sour until it becomes very thick, then heat to 115°–120°.

Pour half of milk into a coarse cloth bag to drain.

Squeeze out as much liquid as possible.

Empty curds into a bowl and crumble.

Repeat process with remaining milk.

Let crumbs set at room temperature for 2 to 3 days (up to 5 days if a stronger flavor is desired).

To crumbs (should be about 4 cups) add baking soda and mix well.

Pour in double boiler and let stand for 30 minutes, then add 1¼–1½ cups warm water.

Bring to boil, stirring constantly.

Mix in butter and salt and finally the cup of hot water, adding it ¼ cup at a time.

Cook for 10–12 minutes, stirring to dissolve crumbs.

Allow to cool, then spread on bread and serve.