Translating into “half-moons,” medialunas are the Argentinean versions of croissants and are often eaten at breakfast or during merienda (snack) with a cup of coffee. They come in two types: de grasa, which are made with lard and are usually flakier and skinnier, or de manteca, a fluffier, doughier version made with butter.
 
For the pastry (makes 12):
6 TB/100 mL milk, warm to the touch
2-7g packages of active dry yeast
250 g/2 cups, loosely packed all-purpose flour
1/2 tsp salt
25g/2TB sugar
1 egg
100g/7TB unsalted butter
jam or chocolate to fill
 
For the glaze
1/4 cup sugar
1/4 cup water
1 tsp vanilla
 
Instructions:
Mix together the water and milk and 1 tsp sugar. Cover, and set aside in a warm place (like the microwave) to proof. Meanwhile, in a large bowl, mix the flour, salt, and sugar together. Form a ring with the dry ingredients, and pour the yeast in the middle. Add the beaten egg and mix gently with a wooden spoon, switching with your hands when the spoon is doing nothing. Wrap the dough and refrigerate for 30 minutes.
Place the butter on a cutting board. Cover with a piece of parchment or wax paper and, with a rolling pin, roll to form a flat square. Set aside.
Once the 30 minutes is up, roll out the dough on a floured surface until1 cm thick. Place the square of butter on top of the dough, centered, with a border of dough around it. Fold the edges of dough so that the butter is still visible. This should form a square. Then fold the square in half to make a rectangle. Finally, fold the rectangle in half to make a smaller square. Wrap the dough and refrigerate for 30 minutes.
Once the 30 minutes is up, roll out the dough until a thickness of 1 cm. Then, just as above, fold the edges of dough to form a square. Then fold the square in half to make a rectangle. Finally, fold the rectangle in half to make a smaller square. Wrap the dough and refrigerate for another 30 minutes.
Once the 30 minutes is up, roll out the dough until a thickness of 1 cm (in a rectangular shape). With a sharp knife, cut the edges to form a rectangle. Then cut the rectangle horizontally in half. You should now have two rectangular strips. Cut congruent equilateral triangles across the strips (in the shape of Pillsbury crescent rolls- come on, you know it). Pull apart and set aside.
Preheat the oven to 350F. Gently pull the corners of the triangles to form a tall triangle. (Tip: they are easier to manipulate when they are close to room temperature.) Fill as desired (or, not at all) and roll the dough to form a crescent. Place on a parchment lined baking sheet.
Bake for 12-15 minutes until golden brown. Meanwhile, make the glaze.
In a small saucepan, combine the sugar and water. Heat until it the sugar dissolves, stirring frequently. Let simmer for about 5 minutes, until the liquid becomes a bit thicker. Add the vanilla and the burner and set aside to cool a little. Once the medialunas are baked, brush on several coats of the glaze. Serve immediately.