Mix the yeast, sugar and warm milk and let it activate for 10 minutes.
Put the flour in a bowl and mix with the milk, yeast and sugar.
Add 2 eggs, yogurt and oil.
Knead until the dough becomes homogeneous (it will still be soft and slightly sticky).
Cover and let the dough rise for about an hour.
Knead again for about 2-3 minutes and cover to let the dough rise for another 30 minutes.
Once it has risen for the second time, roll the soft dough out lightly with your hands on a well dusted surface, or use a rolling pin (the dough will still be quite soft, but will be easier to handle with the flour). You should end up with a 1-1.5cm (1/3-1/2 inch) thick sheet.
Spread your favorite pesto sauce, either basil or ramps, over the entire surface of the dough and gently level with a spoon. Then roll it up tightly from one end to the other.
Using a sharp knife cut the rolled dough in 2 lengthwise, as in the picture below.
Then braid the two halves around one another.
Quickly transfer to a loaf pan lined with parchment paper and let it rise in the pan for another 30 minutes. Meanwhile preheat the oven to 170°C/340°F.
Once the dough has risen in the pan, brush all over with the last beaten egg. Bake for about 1 hour at 170°C/340°F or until the babka has risen, become firm, and has a firm brown crust on the surface.
Leave to completely cool before slicing. You can keep it fresh tightly wrapped in plastic wrap, wax paper or aluminum foil.