While the yeast is bubbling, mix well the flour, salt and sugar.
Make a well in the middle and gently pour in the yeast mixture. Knead until you get a smooth, slightly sticky dough, approximately 5 minutes.
Add one tbsp of butter and knead for a minute. Then add the second tbsp of butter and knead for a minute. Finally add the third tablespoon of butter and knead 3-5 minutes, until the dough absorbs the butter and becomes smooth and non greasy.
Transfer to a lightly dusted surface and shape into a ball. Place the ball in a greased bowl, cover and place in a warm area until doubled in volume, 60-90 minutes.
Grease the bread pan (mine is 20x10 cm) with butter.
Punch the dough to deflate and transfer to a lightly floured surface. Roll the dough into rectangular shape, 20 cm wide (as wide as the longest side of you bread pan) and 1 cm thick.
Roll into a cylinder shape, tuck the edges and place in a pan. Cover with a damp towel, or another bread pan and leave to double in size again, 45-60 minutes.
Place the bread in the middle of the preheated oven (180°C) and bake for 35-40 minutes, or until golden.
Take out of the pan, place on the cooling rack and let it cool completely (!).