Warm the milk until just warm to the touch. Stir in sugar and yeast, and let sit for 5 to 10 minutes until foamy.

Add melted butter, eggs, salt, and remaining sugar. Stir to combine.

Gradually add flour while mixing until a soft, slightly tacky dough forms.

Knead dough for about 6 to 8 minutes until smooth and stretchy.

Cover and let rise until doubled, about 60 to 90 minutes.

Divide risen dough into equal pieces and roll into balls.

Place on a baking sheet, cover, and let puff up for 20 to 30 minutes.

Create wells in the center of each ball for filling.

For fruit filling, spoon jam or cooked fruit into wells.

For sweet cheese filling, mix cream cheese, egg yolk, sugar, and vanilla until smooth; spoon into wells.

Brush edges with melted butter or egg wash if desired.

Bake at 350°F for 15 to 20 minutes until edges are lightly golden.

Let cool for 10 to 15 minutes before serving.