Mix all dry ingredients together (flour, sugar, salt, and yeast) in the bowl of a stand mixer fitted with dough hook. Create a well in the center, and add the eggs and milk into the well.
Mix in the wet ingredients with the dry ingredients. Knead the dough for a minute or so, you may need to use a spatula to scrape down the sides of the bowl. Let the dough rest for 5-10 minutes. Then, mix in the butter in small amounts until everything is incorporated.
Continue to knead the dough for 10 minutes, or until the dough no longer sticks to your hands. Cover the dough with a kitchen towel and let it rise for about an hour.
Separate the dough into small, round pieces. If you're using a kitchen scale, each piece should weigh around 35 grams. Cover the dough balls with plastic wrap.
One at a time, roll out each piece of dough into a flat, oval shape. Add a spoonful of jam to the center. Roll or fold the pastries up, being careful to lock the jam inside by pinching the edges.
Seal the edges and tie each roll into a knot.
Line a baking sheet with partchment paper. Place knots next to each other. Cover with a towel and let the knots proof for 40 minutes.
Preheat the oven to 350°F. Whisk the egg, milk and sugar and brush it on top of the knots. In a separate bowl, mix the flour, sugar, and butter until it forms into crumbs, it's ok if some pieces are bigger.
Sprinkle the knots with the flour crumbs.
Bake the bulochki in the oven until they are golden brown, about 20-30 minutes. Enjoy!