Keep Matcha Green — Bake Low and Slow

Matcha doesn't only lose flavour in a hot oven, it loses its colour: above roughly 170°C the bright green dulls and browns to a muddy khaki. The fix is to bake low and a little longer — around 160°C (325°F / Gas 3) — so the centre of a thick biscuit sets fully without scorching the surface. It's a deliberate trade: a gentler, longer bake instead of a hotter, faster one. If the middle still seems soft, add an extra minute or two rather than turning the oven up. This keeps the vivid avocado-flesh green intact while fully baking a thick slice-and-bake biscuit through.