In a bowl, add warm (warm to the touch) milk, sugar and yeast. Stir and let sit for 10 minutes or until the yeast has frothed up.
Crack the eggs in a large bowl and add salt and butter. Whisk until combined.
Add the yeast mixture and whisk again. Add 2 cups of all purpose flour and mix well until combined.
Add the remaining 3 1/2 cups flour and mix again. Take the dough out on a clean working surface and knead for 5-10 minutes.
Place it in a a greased bowl and cover with cling film. Let sit in a warm place for 1 hours or until doubled in size.
Once doubled, punch it down and knead. Take a handful of dough in your palms and roll into a bowl. Use a rolling pin to flatten it to a thickness of approximately 2 cm.
Use a doughnut cutter to cut out the doughnuts. Place the doughnut in a tray and repeat with the rest of the dough. Cover with a clean kitchen towel and let rest in a warm place for 20 minutes
Fry the doughnuts over a medium flame until golden brown. Take them out on a paper towel to drain the excess oil and the coat both sides with caster sugar (optional)
