Combine the ingredients by pouring the fresh whole milk and muscovado sugar into a large saucepan. Stir the mixture gently over medium-low heat just below a simmer. It’s important to keep the heat low to prevent burning.
Dissolve the sugar as the mixture heats, stirring until the sugar is fully dissolved. This step is crucial, as undissolved sugar can lead to a grainy texture in your finished dulce de leche.
Add baking soda, which will cause a slight bubbling reaction that helps achieve a rich caramel color.
Simmer gently, maintaining the mixture just below a simmer. Stir every 10 minutes for about 2 hours. You’ll see it start to thicken and turn a light brown hue.
Continuous stirring is essential as the color deepens. Lower the heat to the minimum setting until you reach a deep, caramel color and a thick, gooey texture.
Check the texture; if it’s not perfectly smooth, you can strain it through a fine mesh strainer or blend it with an immersion blender.
Allow it to cool down slightly before transferring to a jar, where it will thicken further.
