With spoon, beat butter & 1/4 cup flour til smooth. Lay wax paper out onto a wet cookie sheet. Spread butter/flour mixture into a 12"x6" rectangle on waxed paper. Refrigerate!!
Heat milk, stir in sugar & salt to dissolve. Cool to lukewarm.
Check temperature of water, sprinkle with yeast & stir to dissolve. Add milk mixture and the 3 cups of flour, beating with spoon til smooth. Let rise, covered in warm place, free from draft for 1 hour. Then refrigerate overnight.
Next day, on lightly floured board; roll out dough into a 14"x14" square. Place cold butter mixture on half of dough-remove wax paper, then fold remaining half of dough over the butter; pinching edges to seal. With the fold on your right, use a rolling pin and roll from the center out to form a 20"x8" rectangle.
Now, start with the short side and fold dough in one third. Fold remaining dough over that to form three layers. Seal edges. Wrap dough in foil and chill 1 hour. After 1 hour, unwrap dough with fold at your left and roll out to 20"x8" again. Fold into thirds, wrap & chill 1/2 hour. Unwrap dough with fold at your left and roll out to 20"x8" again. Fold into thirds, and chill overnight.
Next day, roll and fold dough two more times being sure to chill 1/2 hour between. Then chill 1 hour before shaping.
To shape-Cut dough into 4 parts. On lightly floured board, roll each part into a 12" cirlce. Cut each circle into 6 pie shaped wedges. Roll up beginning with wide end. Bring sides together to meet. Place point side down 2" apart on a brown paper bag lined cookie sheet. Repeat with each remaining dough parts.
Cover and let rise til double-approx. 1 hour. Brush with egg yolk that has been beaten with 1 Tablespoon milk. Preheat oven to 425 degrees.
Bake at 425 degrees for 5 minutes. Reduce heat to 375 degrees and bake an additional 10 minutes. Cool on rack 10 minutes.
NOTE: You must follow all the folding steps in order to get the many layers found in a croissant.