Put the sugar in a large saucepan and crush any clumps. Sprinkle 1 teaspoon of water over the sugar to dampen it and set over medium heat. Cook without stirring until the sugar melts to a dark gold, swirling the pan if needed to evenly brown, for 3 to 5 minutes.
2 Tbsp Sugar, 3 Tbsp Hot water
Add the oil and garlic, and cook, stirring, until the garlic is evenly coated and just tender, 1 to 2 minutes.
1 Tbsp Olive oil, 3 cloves Garlic, minced
Add the fish sauce and 2 tablespoons of water, and cook, stirring, until any sugar clumps dissolve and the sauce bubbles, about 2 minutes
2 Tbsp Fish sauce
Add the tofu in a single layer, reduce heat to medium-low, and cover partially. Cook, turning once, for 4-5 minutes. Uncover and continue simmering until the tofu is warmed throughout, for 1 to 2 minutes more.
16 oz Firm tofu, cubed
Remove from the heat, generously grind black pepper all over, and top with cilantro. Serve immediately over rice.
1 tsp Ground black pepper, 2 oz Cilantro, chopped, 16 oz Cooked rice