'Tea biscuit' describes two different baked goods depending on the country. In the United Kingdom, it means a small, lightly sweetened biscuit or cookie served alongside a cup of tea, since British 'biscuit' is what Americans call a cookie. In Canada and parts of the northeastern United States, a tea biscuit is instead a plain, unsweetened, baking-powder quick bread biscuit similar to a scone, meant to be split and buttered rather than dipped.
The British-style tea biscuit developed in the 19th century alongside the rise of afternoon tea, typically made with simple ingredients like flour, sugar, butter, and eggs, producing a tender, subtly sweet crumb that does not overwhelm the delicate flavors of the tea. Common flavor profiles include plain, lemon, vanilla, and cinnamon; the biscuits are usually round or square, about 2-3 inches across, sized for dipping into a cup of tea.
The Canadian tea biscuit is closer to a savory quick bread: flour, baking powder, cold butter or shortening, and milk or buttermilk are cut together and baked hot, yielding a flaky, crumbly biscuit meant to be eaten warm with butter.
Both styles are served as an accompaniment to tea, whether at a British-style afternoon tea or a home meal, and both can serve as a base for desserts like trifles or shortcakes.