In a large mixing bowl, combine the flour, instant yeast, sugar, salt, sunflower oil, and water.
Mix everything together until a dough forms, then knead for 10–12 minutes until smooth and elastic.
Cover the dough and let it rise in a warm place for about 1 hour or until doubled in size.
Once risen, divide the dough into 2 equal portions.
On a lightly floured surface, roll each portion into a large round sheet.
Spread the softened butter evenly over one dough circle. Place the second dough sheet on top.
Cut the layered dough into 12 triangle-shaped wedges.
Gently stretch each triangle slightly, then roll from the wide end toward the pointed tip to create croissant shapes.
Place the shaped rolls onto a parchment-lined baking tray.
Brush the tops with beaten egg for a shiny golden finish.
Let the rolls rise again for about 30 minutes until puffy.
Preheat the oven to 200°C (392°F).
Bake for 10–15 minutes or until golden brown and lightly crisp on the outside.
Allow to cool slightly before serving warm.