Start by pouring the whole milk into a large pot. Using medium heat, bring the milk to a gentle simmer. Stir it occasionally to avoid scorching the bottom. It should take about 10 minutes. You want to see small bubbles forming around the edges; that’s your cue.

Once your milk is simmering, remove it from the heat. Now, it’s time to add your vinegar. Pour in the vinegar and give it a gentle stir to combine. You'll see the milk start to curdle, which is exactly what you want! After a minute, let this mixture sit for about 5-10 minutes to allow the curds to fully form.

Grab a fine-mesh sieve or cheesecloth and place it over a bowl. Carefully pour the curdled milk into the sieve, allowing the whey to drain away. What you are left with in the sieve is your cheese!

Rinse the curds under cold water, which helps remove the vinegar’s taste while also cooling it down. After rinsing, sprinkle in the salt and the lemon zest, if you’re using it. Mix it gently with your hands to ensure even distribution of the flavor.

At this point, you can shape your queso fresco. Pack the cheese into a container. If you prefer uniform shapes, press it into a tight ball or patty. Cover it with plastic wrap and let it sit at room temperature for about an hour to firm up.