Heat milk until lukewarm, then melt butter into it.

Dissolve yeast and 1 tsp sugar in part of the warm milk mixture and let it foam.

Combine flour, salt, and remaining sugar in a bowl.

Make a well in the dry ingredients and pour in the milk-yeast mixture.

Mix until smooth, cover, and let proof in a warm place.

Add remaining milk, egg, and orange zest.

Knead until smooth, cover, and let proof again.

Preheat oven to 350°F (175°C).

Line a baking sheet with parchment paper.

Divide the dough into 9 equal pieces.

Divide each piece into 3 smaller pieces and roll into balls.

Arrange the balls in triangle shapes on the baking sheet.

Cover and let proof.

Brush with condensed milk.

Bake until golden brown.

Cool on a wire rack before serving.