Pour the milk into a large, heavy bottomed saucepan to prevent scorching. Add the sugar and stir gently over medium heat until it dissolves completely. Do not allow the milk to boil at this stage.

Stir in the bicarbonate of soda, vanilla, and a small pinch of salt. The mixture will foam slightly, which is normal. The bicarbonate helps prevent the milk proteins from curdling during the long cooking process.

Lower the heat to a gentle simmer. Stir frequently using a wooden spoon or heatproof spatula, scraping the bottom of the pan to prevent sticking. Continue this for about 45 minutes, keeping the heat steady.

As the mixture thickens and deepens in colour, stir more often to prevent burning. The milk will gradually turn a golden caramel shade, releasing a nutty, sweet aroma. Patience is key here; allow it to develop naturally.

After around 1 hour and 15 minutes, test a small spoonful on a cold plate. If it holds a soft shape and spreads like thick caramel, it is nearly ready. Continue cooking if it still runs easily.

Once it reaches a thick, glossy texture that coats the spoon, remove it from the heat. Remember that Arequipe thickens slightly as it cools, so stop just before it reaches the final firmness.

If you used a vanilla pod, remove it. For a perfectly smooth finish, strain the Arequipe through a fine sieve into a clean bowl. This step ensures a professional, silky result.

Allow the Arequipe to cool to room temperature before transferring it to sterilised glass jars. Seal tightly and refrigerate once cooled completely.

Serve Arequipe as a spread over toast, a filling for pastries, or a topping for ice cream and fruit. It is a classic addition to obleas (Colombian wafers).

For a charming finish, drizzle over desserts and sprinkle with a few flakes of sea salt for contrast. The subtle salt enhances the caramel notes beautifully.