To make the dough: Place flour, sugar, and yeast in the bowl of a standing mixer fitted with the dough hook and mix on low speed until combined. Stir in salt. Add eggs and sour cream and mix until dough comes together, 2-3 minutes. While mixer is running, add butter, a few cubes at a time, and mix until incorporated, about 1-2 minutes. Continue mixing for another 8 minutes on medium speed, until dough is smooth and pulls away from the sides of the bowl (it will still stick to the bottom, that’s ok). During mixing, scrape down the sides of the bowl using a spatula as needed.
Transfer dough to a large bowl brushed with oil (the fat will keep the dough from drying out), cover with plastic wrap, and leave in the fridge for at least 6-8 hours or overnight.
To make the filling: Mix all ingredients as little as possible, just until combined. Don’t overmix or else the filling will become too thin. It's ok if it's still grainy.
Grease two loaf pans (I used 9×4 inch) with oil and line the pans with parchment paper, leaving enough overhang on the sides for easy release of the bread later. Set aside.
Rolling and shaping: Divide dough in half. Roll out each half on a lightly floured surface and shape into a rectangle measuring 16×14 inches (40×35 cm). Spread half of the cheese filling over each rectangle, leaving a small border around the edges of the dough. Roll up the dough like roulades, starting from the long side closest to you and ending at the other side. Press to seal the ends and rest the rolls on their seams. Carefully lift bread into pans. Cover pans loosely with plastic wrap and leave to rise on the counter for 1½ -2 hours.
Preheat oven to 340°F/170°C.
When bread is ready, remove plastic wrap and place pans on middle rack of oven. Bake for 25-30 minutes until golden brown. Allow to cool completely on a wire rack. Serve warm or at room temperature.
Bread will stay fresh for 24 hours in an airtight container at room temperature. It also freezes well for up to 2 months. To thaw, leave overnight in the fridge, or rewarm in oven.