Peppered Queso Blanco Cubes with Watermelon

Steps

1. Wash a large heavy pot, a slotted spoon, a colander and a thermometer in hot soapy water, and line the colander with a double layer of clean damp cheesecloth set over a bowl.
2. Measure the lemon juice into a small cup; it is the acid that sets the cheese, and all of it goes into the milk.
3. Pour the milk into the pot and heat over medium, stirring often so it doesn't scorch, until steaming and 190°F (88°C) on the thermometer.
4. Take the pot off the heat and slowly stir in the lemon juice in a thin stream. Within a minute the milk breaks into soft white curds floating in thin, clear yellow-green whey; stir gently once or twice more until no milky liquid remains.
5. Let the curds rest undisturbed for 10 minutes so they firm up.
6. Ladle the curds into the lined colander and let the whey drain for 5 minutes; discard or chill the whey.
7. Sprinkle the salt over the warm curds and toss gently with a clean spoon.
8. Gather the cloth, twist it into a tight bundle, flatten it into a square about 1 inch thick, and set it on a plate with a second plate and a heavy can on top. Refrigerate at 40°F (4°C) or below and press for 3 to 4 hours until firm and sliceable. You'll have roughly 300 g of cheese, about 75 g (a scant 2/3 cup of cubes) per serving.
9. Unwrap the cheese and cut it into 3/4-inch cubes.
10. Mix the cracked black pepper and oregano on a plate, then roll the cheese cubes in the pepper mixture to coat.
11. Toss the watermelon with the lime juice, arrange it beside the cheese cubes, and drizzle the olive oil over the cheese.
12. Serve right away. Refrigerate leftover cheese promptly and use within 3 days; the cheese is fresh and not aged.