Combine the dry ingredients. In a large bowl, stir together the flour, sugar, salt, and instant yeast.
Warm the liquids. Place the oil, sparkling water, milk, and yogurt in a small saucepan. Warm gently over low heat, stirring until lukewarm. Do not let the mixture become hot.
Make the dough. Pour the warmed liquid mixture into the dry ingredients. Stir until a dough forms, then knead until smooth and elastic.
Divide and rest. Divide the dough into two equal balls. Cover and let rest in a warm place for 15 minutes.
Roll and butter. On a lightly floured surface, roll one dough ball into a large circle. Spread evenly with half of the softened butter, keeping the second dough ball covered.
Shape the crescents. Cut the circle into 16 equal wedges. Roll each wedge from the wide end toward the pointed tip. Arrange on a parchment-lined baking sheet with the tip underneath, leaving room between the rolls.
Repeat. Roll out the second dough ball, spread with the remaining butter, and shape another 16 crescents. You should have 32 rolls total.
Let rise. Cover the rolls loosely and leave in a warm place for approximately 1 hour, until visibly puffy. Toward the end of the rising time, preheat the oven to 400°F (200°C).
Add the topping. Whisk the egg with 2 tablespoons of milk. Gently brush over the risen rolls and sprinkle with sesame seeds.
Bake. Bake for approximately 20 minutes per batch, until golden brown and baked through. Transfer to a wire rack and cool slightly before serving.
