Purple Amaranth with Red Fermented Tofu

Name: Purple Amaranth with Red Fermented Tofu (Nan Ru Xian Cai 南乳莧菜)
Cuisine: Chinese
Ingredients: ½ tsp caster sugar; 1 tbsp red fermented tofu, mashed with 1 tbsp liquid from the jar; 2 tsp finely chopped garlic; 3 tbsp cooking oil; 250 g purple amaranth leaves (discard any thick stalks)