Take 1-2 tbsp of butter at the time and knead until fully incorporated into the dough. The dough will break every time you add new portion of butter, but don’t worry it will come together. Don’t be inpatient and add too much butter at once! This part of kneading process may take about 20-25 minutes. By the time you are done the dough temperature should be 25-26°C (77- 79°F)