In a bowl sprinkle 1 envelope yeast over 1 cup warm water to soften. Stir in 1 cup flour, 3/4 cup evaporated milk, 1 egg, 1/3 cup sugar, 1/2 stick or 1/4 cup butter, melted, and 1 1/2 teaspoons salt. Stir the mixture until it is smooth and set it aside.

Put 4 cups flour and 2 sticks or 1 cup cold butter in a large bowl. With a pastry blender or two knives, cut in the butter until it is the size of kidney beans. Add the yeast mixture and stir the dough only until the flour is moistened. Cover the bowl tightly with plastic wrap and refrigerate the dough for at least 4 hours or up to 4 days.

Put the ball of dough on a lightly floured board and knead it about 6 times. There will still be sizable pieces of butter in the dough. Divide the dough into 4 parts and roll 1 part at a time into a circle about 17 inches in diameter, always refrigerating the remaining dough.

Cut each circle into 8 wedges and roll up each wedge starting at the broad end. Put the rolls on ungreased baking sheets and shape them into crescents. Cover them lightly with a tea towel and let them stand at room temperature for 1 hour or until the dough has risen.

Brush the tops with 1 egg mixed with 1 tablespoon water and bake the croissants in a 325 degree oven for 35 minutes.

To reheat the croissants, arrange them in a single layer on a baking sheet and bake them in a 350 degree oven for 10 minutes. They can also be frozen. Makes 32 croissants.