After many tries, these are the butter brands with the best results for clearly separated layers and a light flaky pastry. 

I also know for sure that 82% fat butter of lower quality will ruin the recipe - you will be eating croissants, but they won't have the best taste.

Measure and prepare all the ingredients, also now it's time to get the butter from the fridge.

In a bowl, put the flour, sugar, salt, dried yeast and, finally, a cup of water (room temperature).

Add a small cube of butter, 50g. I microwave it for 10 seconds before, to make it softer and incorporate more easily in the dough. 

Now start kneading by hand to mix all the ingredients.

Turn dough onto table (no flour!) and keep kneading by hand. 

Notice that at first it's sticky and rough, but in a few minutes it changes and starts to become smoother and softer.

This is what it looks like when it's ready, I feels so nice and it's not at all sticky.

Flatten dough out with your hands, make a rectangle and place on a plate lined with plastic wrap. 

Cover with plastic wrap and refrigerate for 2-3 hours, even overnight.

Cut the rest of 130g butter into small cubes and arrange them on a big sheet of parchment paper.

Shape the parchment paper into an envelope/packet about 18-20cm long and 10cm wide. Place it on the table folded side down. 

In the picture you can see my metal ruler, you can find one in any hardware store and it's useful when you need to be precise in the kitchen. You can use any other ruler or measuring tape.

Using a rolling pin, carefully roll out the butter wrapped in parchement paper to obtain an even layer inside the envelope. 

Leave wrapped and chill for 2-3 hours, just like the dough.

After 2-3 hours take the chilled dough and butter out of the fridge. 

Spread out dough with the rolling pin on the lightly floured table and make a rectangle 3 times bigger than the butter envelope.

Notice in the picture that, butter placed in the middle, the sides will cover it perfectly when folded over. And the width will be the same, so there will be no dough above or below the butter. 

Here it's very important that both the butter and the dough are chilled, but elastic. See in the picture how I test the butter, lift gently and, if it doesn't break and it's flexible, you can continue. If not, leave it for 2-3 more minutes to get softer, but not too soft. 

If the butter is too cold and hard, it will tore the dough and won't form clearly separated layers and if it's too soft, it will blend into the dough and won't give the flaky texture.

When butter reaches the right texture, bring the sides of the dough in the middle, wrapping the butter in.

Then place the rolling pin in the middle of the dough and start pulling it upwards, then downwards. The moves have to be gentle, but firm, we want to distribute evenly the butter inside the dough, without tearing it.

Continue like this (don't forget to flour the table, so dough doesn't stick), until it's 50-60cm long. 

Notice I don't move the rolling pin to the right, nor to the left and the dough looks like an elastic band.

Then take the ends and fold them over - one should cover 2/3 and the other 1/3 of the entire space.

Then refold in half.

This kind of folding is called "double fold" or "tour double" and the process, "tourage". Make sure there isn't flour left on the dough when you do the "tourage". 

Wrap dough in plastic foil, place on a flat plate and refrigerate for 30 minutes.

After this time, remove dough from the fridge and place on the table with the edges open towards either left or right, just like a closed book. Here it's towards the left. 

What matters here is that every time you keep the same direction you chose first - either left or right.

Now spread it out again, from the middle to the up and down ends to obtain a 40-50cm long pastry strip.

Now bring one end over 2/3 of the strip.

And fold the other end over the first one. 

This is called "single fold" or "tour simple". 

So, we've made a "tour double" and then a "tour simple" so far. We are done with the folding and we let dough rest in the fridge for at least 1 hour, or more. 

Don't forget to cover with plastic wrap.

Remove pastry from the fridge and start shaping the croissants. 

First of all, place it with the open edge of the book towards you, which was originally to the left.

Using a rolling pin make up and down moves to roll out a 25cm long strip. 

This is going to be the long side of the pastry strip. 

Now rotate the edge of the "book" to the left, see in the picture. 

It's the same position in which you made the "tourage".

Roll out dough to obtain a 40cm long strip, with up and down moves starting from the centre. 

This is going to be the wide side of the pastry strip.

Now turn the book open end downwards, so that you face a 40x25cm rectangle. 

Notice that all the edges are relatively straight, if you work gently and make sure to flour the table, dough will spread nicely and evenly.

With the ruler, measure and mark every 8cm on the long side using a knife or a pizza cutter.

On the opposite side, you can use the ruler to mark every 4 cm, but I approximate - about half the distance between every 8cm on the opposite side.

Then I cut the triangles for the croissants with the pizza cutter/knife. 

I use the ruler to get perfectly straight borders. Instead of a ruler, you can use any other straight-edged surface - the side of a pan, a cutting board, a box etc.

This way we get 9 perfect croissants and 2 more from the borders, which won't be perfectly shaped, but still tasty.

Roll each croissant, as tight and neat as possible. 

See that each has 4 layers.

Place croissants on a baking tray lined with parchment paper - spaced well apart, they will get a lot bigger later on. 

Cover with plastic wrap and let rise for 2 hours at room temperature.

After this time, remove the plastic wrap and carefully brush the croissants with raw egg white. 

The moves start up and go down, on the lenght of the croissant.

Make sure you preheat the oven to 200 degrees C, so you should turn it on when the croissants have rested for 1 hour and a half. 

Bake croissants in the preheated oven to 200 degrees C for 15 minutes, then for 5-10 more minutes in the heated oven to 180 degrees. It also depends on the oven you have.

If the oven is not preheated, even with the right temperature, the butter will melt and come out and the croissants will be super oily and droopy.

They are perfect when served warm, 20-30 minutes after they've been removed from the oven. And they are great even reheated...

Here I want you to see the difference between the 2 types of butter - the one above is made using low quality butter - there are no layers, it's a soft pastry, still tasty, but it's not a croissant. The butter is too soft and watery, it will just blend into the dough and won't be able to separate the layers.  

The one below was made using best quality butter, you can see the clearly defined layers. 

Enjoy!