Cornstarch Alfajores with Dulce de Leche

Before you start

Alfajores are sandwich cookies found across South America and Spain in many forms. This version, alfajores de maicena, is the delicate kind popular in Argentina, Uruguay and Peru: two soft, crumbly cookies made mostly from cornstarch, joined with a thick layer of dulce de leche and often rolled in coconut around the edge.

Cornstarch is the key decision. With twice as much cornstarch as wheat flour, the dough develops very little gluten, so the cookies are fragile and almost powdery rather than crisp. They should come out of the oven pale, with barely colored bottoms; browning dries them out and dulls the milky flavor. Use a thick dulce de leche (sold as repostero, or pastry style) so the filling stays put instead of oozing out.

Ingredients

• Cookies200 g (1⅔ cups) cornstarch
• 100 g (¾ cup plus 1 tbsp) all-purpose flour
• 1 tsp baking powder
• ½ tsp baking soda
• ¼ tsp fine salt
• 115 g (½ cup) unsalted butter — softened
• 75 g (6 tbsp) granulated sugar
• 3 large (about 54 g) egg yolks
• 1 tsp vanilla extract
• 1 tsp finely grated lemon zest
• 1 tbsp brandy or pisco — optional; or 1 tbsp milk
• Filling360 g (about 1 cup) thick dulce de leche — pastry-style (repostero)
• 40 g (½ cup) unsweetened shredded coconut
• 2 tbsp powdered sugar — for dusting (optional)

Method

1. Whisk the cornstarch, flour, baking powder, baking soda and salt together in a bowl.
2. Beat the butter and sugar on medium speed for 2 minutes, until pale. Beat in the yolks one at a time, then the vanilla, lemon zest and brandy.
3. Add the dry ingredients on low speed and mix just until the dough comes together. It will feel soft and a little crumbly; press it into a flat disk, wrap and chill for 30 minutes.
4. Heat the oven to 175°C (350°F) and line the sheets with parchment. Roll the dough between two sheets of parchment to 5 mm (scant ¼ in) thick. If it cracks at the edges, press it back together; it is forgiving.
5. Cut 5 cm rounds and lift them carefully onto the sheets 2 cm (¾ in) apart. Gather and re-roll the scraps once.
6. Bake one sheet at a time for 9 to 11 minutes, until the cookies are puffed and set but still pale on top, with bottoms only faintly golden. Cool them on the sheet for 5 minutes, then move them to a rack; they are fragile while warm.
7. Match cooled cookies into pairs of similar size. Spread or pipe about 1 tablespoon (12 g) of dulce de leche on the flat side of one cookie, leaving a thin margin, and press a second cookie on top until the filling reaches the edge.
8. Roll the exposed edge of filling in the shredded coconut. Dust the tops with powdered sugar if you like.

Tips for success

• If the dough is too soft to lift after cutting, slide the parchment onto a tray and chill it for 10 minutes before transferring the rounds.
• Bake a single test cookie to see how your oven colors them. You want just-set, pale cookies with a matte top.
• If you make your own dulce de leche, cook it until a spoonful dropped on a cold plate holds its shape before using it as a filling.

Substitutions

All-purpose flour

For a gluten-free cookie, use 100 g sweet rice flour. The texture stays tender; check that the baking powder is gluten-free too.

Thick dulce de leche

Canned dulce de leche can be thin. Stir it in a saucepan over low heat for 5 to 10 minutes until thicker, then cool, or chill the filled cookies so it firms.

Shredded coconut

Roll the edges in finely chopped toasted walnuts or leave them plain. For a chocolate version, dip the whole sandwich in melted dark chocolate.

Variations

Chocolate-covered alfajores

Dip filled sandwiches in 250 g melted dark chocolate and set on parchment. This style is common in Argentine shops.

Lemon alfajores

Double the lemon zest in the dough and fill with lemon curd mixed into the dulce de leche at a 1 to 3 ratio.

Troubleshooting

Cookies are dry and crunchy

They baked too long or browned. Pull them while still pale and set, and keep the dough 5 mm thick so the centers stay soft.

Dough crumbles and will not roll

It is too cold or slightly dry. Let it warm for a few minutes and knead it briefly; add a teaspoon of milk if it still cracks badly.

Filling squeezes out when you bite

The dulce de leche is too thin or there is too much. Thicken it, use about a tablespoon per sandwich and let the assembled cookies rest an hour before serving.

Storage

Keep filled alfajores in an airtight container at room temperature for up to 3 days, or in the refrigerator for up to 1 week in a warm kitchen. Unfilled cookies keep for 5 days airtight, or freeze them for up to 2 months.

Safety notes

Contains egg, wheat, milk and coconut. The unbaked dough contains raw yolks and should not be eaten.