Prepare the dough:

1. In small cup, dissolve yeast in water and stir to mix together (the mixture should start to bubble and develop a yeasty aroma). Let it sit for 2 minutes.
2. In a large bowl, add flour, sugar and salt. Pour in yeast mixture and whisk until fully combined, scraping down the sides of the bowl (there should be no dry flour particles visible).  Add 20 grams butter in dough mixture and incorporate it into the dough by kneading for a few seconds. 
3. Cover with plastic wrap and let it sit at room temperature for 1.5 to 2 hours, until the dough doubles in size. (Note that a higher room temperature will speed up the fermentation process and will cause the dough to rise faster).
4. Place dough on a lightly-floured surface and press gently to squeeze out the air. Roll the dough into a log, and then cut into 12 equal pieces.
5. Take one piece of dough and and use a rolling pin to roll it out into a rectangle approximately 6 x 10-inches. Apply a generous amount of butter on the dough and spread evenly all over.
6. Take another piece of dough and roll it into the same size and stack it on top of the first piece. Apply a generous amount of butter and spread evenly all over. Repeat to produce a multi-layered dough with alternating layers of rolled out rectangular-shaped dough and butter, ending with a layer of dough.
7. Wrap the stacked dough with cling film and refrigerate for at least an hour or overnight to cool down completely.

Shape the dough:

1. Take out the stacked dough and roll it out into a larger rectangle, approximately 10 x 18-inches.
2. Make 3 even horizontal cuts using a pizza cutter, to form 4 smaller rectangles, each measuring approximately 4.5 x 18-inches. Cut each of these rectangles in half diagonally to form 8 triangles (or initially cut dough in a zigzag pattern into 8 equal triangles).
3. Take each triangle and tightly roll it up from the base of the triangle into a crescent shape. Tuck the tip underneath and place the croissant with the tip side down onto a parchment-lined baking pan. This is important because if the tip is not tucked under, it will rise and possibly detach from the croissant. Repeat with the rest of the triangles, and place them 2-inches apart on the baking pan.
4. Let the croissants rise at room temperature for 1.5 hours, or in a cooler place for 2-3 hours. Once ready, the croissants will start to puff up and almost double in size.

Bake the croissants:

1. Preheat oven to 425 F. 
2. Apply egg wash on each croissant.
3. Bake at 425 F for 10 minutes, then turn the temperature down to 375 F and continue to bake for another 12 minutes until they turn golden brown.
4. Remove croissants from the oven and place on a wire rack to cool for at least 10 minutes.