Combine yeast and warm water, stirring a little to dissolve yeast. Let sit about 10 minutes. Add 1/2 of flour; add water and honey; whisk until smooth. Cover bowl and let stand 1 1/2 hours.
Combine remaining flour with butter, and flatten butter pieces. Pour yeast batter into flour mixture; fold together with spatula; just moisten flour without breaking butter pieces.
Turn dough onto lightly floured surface. Pat dough down and roll into a 18" x 12" rectangle; if too sticky, sprinkle with flour. Use a metal spatula to fold 1/3 of dough toward center; then fold from other side, 1/3 of dough over first 1/3. Lift folded dough off work surface, and scrape surface clean. Sprinkle work area with flour and repeat, rolling and folding 3 more times. Dough must be hard; if not, freeze for 45 minutes.
Pat dough into rectangle. Cut into parts, 1 part for each 4 croissants. For instance, for 24 croissants: cut in 1/2 lengthwise, then cut each half into 3 pieces, for a total of 6 (4x6=24). Work with one piece at a time, holding others in refrigerator until ready to use. Roll each piece individually into 5 1/2" x 14" rectangles. Cut into two 5 1/2" x 7" pieces. Cut each piece diagonally to form 4 triangles; roll from wide end to point. Place on ungreased cookie sheets. Curve ends to crescent shape.
Beat egg with water; brush croissants with this and set them aside 1 hour. Reglaze with egg/ water mixture. Bake at 375 degrees until puffed and brown. Let cool slightly and serve.