'Old tofu' has two almost opposite meanings that depend on region. In most of China
老豆腐 means firm/pressed tofu, the counterpart of
嫩豆腐 (soft tofu). But in Beijing and Tianjin,
老豆腐 is a breakfast dish — very soft tofu curd served with soy sauce, sesame paste, and pickles, essentially a saltier sibling of
豆腐脑. Read context carefully.