In the bowl of your standing mixer sift and combine flour, salt, ground nutmeg and sugar. Set aside.
In a glass or a small bowl, combine active dry yeast, teaspoon of sugar and lukewarm water. Let it rest for 5 minutes until the top becomes frothy.
In the meantime, warm your milk (but don't let it boil) and pour it over the butter which you've previously cubed and put in a medium sized bowl. The milk should melt the butter and everything should be body temperature prior to using.
Now, add the whisked eggs, yeast and butter/milk mixture to the flour mixture, fit your standing mixer with a dough hook and let it knead on medium-low speed for about 10 minutes. The dough is ready when it starts pulling away from the sides of your bowl and is soft to the touch.
Transfer the dough to a large bowl which you've previously floured or lightly greased so it doesn't stick. Cover with a clean tea towel or cling film and allow it to rise in a warm place for about an hour or until it doubles in size.
Once your dough is ready, punch it a little to deflate it, transfer on a clean, floured surface then roll the dough to about 1.5 to 2 cm thick. (around ½ inch to ¾ inch). Using a 5 cm (2 inch) heart shaped cookie cutter, cut the dough into hearts and place on a baking sheet lined with baking paper. Cut a little triangle on the crease of each doughnut to make sure they keep heart shape. Cover with a clean tea towel or plastic wrap and let them rest and rise for another 20 to 30 minutes.
You don't want to overproof your doughnuts, otherwise they will become hollow inside. When the dough is ready, heat approx. 1 litre of vegetable oil in a heavy-bottomed pan. Oil should be between 170 and 180 degrees Celsius. That's around 340 to 350F.
Fry 3-4 doughnuts at a time for a couple of minutes on each side or until golden. Take them out to a plate covered with paper towels. Let them cool completely before filling and covering with sugar.
Notes
If you don’t have a stand mixer, you can use an electric hand mixer with dough kneading attachments or a wooden spoon.
If you still don’t own one, I advise you to buy a kitchen scale – they’re cheap and easy to use, and always guarantee the same results in baking!