Homemade manjar (Chilean dulce de leche)

They are the same sweet under different names: milk and sugar reduced until they caramelise. In Chile it is called manjar; in Argentina, Uruguay and much of Latin America, dulce de leche; in Colombia and Venezuela, arequipe; in Mexico, cajeta when made with goat's milk. The real differences are in the set (Chilean manjar is usually a little firmer) and in the amount of sugar: this recipe uses 250 g per litre, less than many Argentine versions.

It curdles when the milk is slightly acidic (not very fresh, or opened days ago) or when it boils hard at the start, because the protein coagulates into lumps. The baking soda neutralises that acidity: do not skip it. Use fresh whole milk, heat over medium heat and turn it down to the lowest setting as soon as you add the baking soda. If lumps still appear, pass the finished manjar through a blender or a fine sieve.

It crystallises when sugar crystals are left on the sides of the pan and fall into the sweet once it is already thick, or when it cools too quickly. Dissolve the sugar well at the start, scrape the sides with the spoon every time you stir and do not put the manjar in the fridge until it is lukewarm. If it has already turned grainy, warm it with 2-3 tablespoons of milk over low heat, stirring until smooth.

Yes, it is the best-known shortcut: put the closed can, label removed, in a pan completely covered with water and simmer it gently for 2 hours for a spreadable manjar or 3 for a firm one, topping up with hot water so the can is never uncovered. Let it cool completely in the water before opening it, never while hot. It comes out sweeter and a little paler than the manjar made with fresh milk in this recipe.

In a clean, covered glass jar, up to 3 weeks in the fridge. It has no preservatives, so always use a clean spoon and do not leave it out for more than a few hours. It also freezes for up to 3 months in an airtight container; thaw it in the fridge and stir before using. If it has set very firm as it cooled, warm it for a few seconds in a water bath.

It stays pale when the baking soda is missing, which is what speeds up browning and gives the caramel colour, or when it is taken off too early. It stays runny when it has not reduced enough: allow 1 hour 45 minutes in total and go by the spoon-trail test, not the clock, because the time changes with the width of the pan and the strength of the heat. If it is runny once cooled, cook it again over low heat, stirring, until it reaches the point.

Firmer than the spreadable one: after the 2-second trail test, cook 5 more minutes stirring constantly, until the trail stays open and a drop placed on a cold plate does not slide when tilted. That way the filling does not ooze out between the hojarasca layers or soak into the dough. Let it cool completely before assembling the alfajores and fill with a piping bag or a spoon.