In a heavy-bottomed saucepan, combine the evaporated milk, one cup of sugar, and the lime rind if using. Stir well to combine all the ingredients.
Place the saucepan over medium heat. Stir frequently until the sugar completely dissolves. This should take about 5 minutes.
Once the sugar is dissolved, reduce the heat to low and continue to cook the mixture. Stir constantly to prevent it from sticking to the bottom of the pan. Cook for about 30-40 minutes until the mixture thickens and turns a caramel color.
To check if your dulce de leche is ready, use a candy thermometer; it should reach around 240°F (115°C). Alternatively, drop a small amount onto a plate and let it cool for a minute. Run your finger through it; if it holds its shape, it’s ready!
Once thickened, sprinkle in the additional tablespoon of sugar. Stir well for a couple of minutes to incorporate it fully.
Remove from heat and pour the mixture into a prepared baking dish or mold. Spread it evenly and let it cool at room temperature until it sets.
Once completely cooled and firm, cut the dulce de leche into squares or rectangles. Enjoy your homemade Dulce de Leche en Tabla as a delightful treat!
