1. Preheat your oven to 225 degrees Celsius, or 437 degrees Fahrenheit.

2. In a small bowl, combine warm milk and yeast, stirring gently to dissolve the yeast, and let it sit for 10 minutes to activate.

3. In a large mixing bowl, whisk together the flour, sugar, and salt. Add softened butter and mix until the mixture becomes crumbly.

4. Next, add the yeast mixture and egg to the dry ingredients and mix until a shaggy dough forms.

5. Knead the dough on a floured surface for 10 minutes until it becomes smooth and elastic. Place the dough in a greased bowl, cover it with plastic wrap, and let it rise in a warm, draft-free place for 1 to 2 hours.

6. Punch down the dough and divide it into 10 equal pieces. Shape each piece into a ball and place them on a baking sheet lined with parchment paper, leaving about 2.5 centimeters, or 1 inch, of space between each ball. Cover with plastic wrap and let them rise for another hour.

7. Brush the tops of the balls with a beaten egg mixed with a little water, then sprinkle with sesame seeds. Bake in the preheated oven for 15 minutes, or until golden brown.