Mix together warm milk and dry yeast and set aside.
In a large bowl or in the bowl of a stand mixer mix together 2 of the eggs and egg white from the third egg with 1/2 cup sugar, until sugar is dissolved.
Add milk and yeast mixture. Continue mixing on low speed.
Add oil, lemon juice and vanilla extract.
Add half of the flour and mix until well incorporated. Add salt and lemon zest.
Now if using stand mixer you can switch to the dough hook.
Continue gradually adding the remaining flour mixing on low speed. Once the dough comes together, increase the speed to medium and mix until smooth for 5 more minutes.
Transfer dough to a large lightly greased and floured bowl and cover with plastic wrap.
Let it rest in a warm place until it doubles its size. It usually takes me 2 hours to have the dough double, but time can vary depending on the temperature in your home.When there is sugar in yeast dough, it takes longer time for it to rise.
After the initial rise, turn the dough onto a lightly breaded surface and divide it into 6 equal parts. You can make the rolls a little bigger than mine and divide the dough into 4 parts.
Roll each ball of dough into 11-inch (28-cm) round.
Brush each round with some butter.
Using a sharp knife cut the dough round into 8 equal pieces.
Spread about a teaspoon of rose hip jam at the wide end of the triangle. Roll the dough into a crescent shape, forming a C. Make sure the pointed end is positioned under the roll, so it doesn't open during baking.
Continue rolling all wedges of the dough.
Place on a baking sheet lined with parchment paper or aluminum foil. (If using foil make sure it is lightly greased and floured). Allow them to rise until they double their size before baking.
Gently brush them with egg, oil and milk mixture. Sprinkle each roll with some sugar.
Bake on 350F (175C) for 15-20 minutes until rolls turn golden.