Up until now, I have used the term "butter" to refer to either butter or margarine. It's just easier to type butter, and most people understand they're interchangeable. For croissants, you should spring for the good stuff for two reasons. First, you're making croissants. And second, the melting point of butter is different, and it hardens up better into the flat sheet you need to make. Margarine never really becomes completely solid.
This is actually my own recipe. I came up with it using techniques I learned from various sources, but it's mostly using the proportions I have devised for every bread I make. Reading the recipe card (I haven't made these in a couple of years), I realized how poorly I wrote the instructions. Well, I knew what I was talking about. I'll try to make this a little more precise.
This is also a half-recipe because, at the time, I hadn't bought my big bread board. A half was all that would fit on my old one. To use a full package of yeast, just double this and hope you have a big enough work space.
1 tsp yeast
1 C milk
1 tsp sugar
2 C flour, plus more for dusting
1/4 tsp salt
4oz unsalted sweet butter (1 stick, 1/2 C)
1. Warm milk and sugar to 100ºF. Dissolve yeast in milk and let sit until foamy, 5-10 minutes.
2. Sift together salt and 1 C flour. Stir milk into flour mix. Beat into a batter for 2 minutes.
3. Add 1 C flour and beat to make a very soft dough. Turn out onto kneading surface and knead until smooth, adding as little flour as possible. Round, place in greased bowl, and let rise in a warm place until doubled, about 1 hour.
4. Let the stick of butter come to room temperature. Roll out butter into a 7"x12" (approx) rectangle between two sheets of plastic wrap. Place on a flat surface and chill in refrigerator, at least half an hour.
5. Punch down dough and let rest 10 minutes. Roll into a rectangle approx 8"x18", or big enough that the sheet of butter will cover 2/3 of it with a little room around the edges. Place butter on the dough:
6. Fold the left side towards the right, like closing a book, but stop halfway across the buttered side. Then fold the right towards the left, until you get an aligned rectangle. Think of a tri-fold takeout menu. Roll the dough out to full size and do it again, which will be the other way. Try to line up the edges, but it's OK if they aren't perfect. Place dough in refrigerator to rest for 20 minutes.
7. Take out dough and roll out again. This will be the second "turn". Fold and place back in the fridge for 20 minutes. If you need a trick to keep count, make a single dent in the dough with a finger the first time you do it, two dents the second time, and yes, there will be a third. What you're doing is building flakey layers, and three turns seems to be the universally accepted number for a croissant.
8. After the third turn, the dough is ready. You can use it right away, or let it develop some character by letting it sit in the fridge at least four hours or overnight.
9. Roll the dough out 1/4" thick, which will be a rectangle approx. 7" x 16". Cut four rectangles 4" x 7", then cut each rectangle in half diagonally. Pull gently at the corners of the wide end, then roll up towards the point. Curve slightly, and place on greased (or silpat) cookie sheet with the point underneath. For filled croissants, cut each rectangle in half across the middle, making two rectangles. Place a tablespoon of filling (chocolate, cream cheese, pie filling) in the middle, then do your book fold again to make a new rectangle. Place seam-side down on cookie sheet.
10. Brush shaped croissants with melted butter or beaten egg. The butter adds flavor, the egg makes them darker. Your choice. Proof in a warm place until doubled, about 1 hour.
11. Bake at 375º for 20 minutes, until golden.
Difficulty rating $@%!