Pre-heat oven at 180C or 160C with fan
In a ~30cm baking dish, add the frozen berries, mix with the chia seeds, vanilla extract, lemon juice and optional maple syrup
In a bowl, combine everything for the crumble topping, including oats, nut butter, maple syrup, walnuts, ground flax, cinnamon and pinch of salt. Once well combined, top the berries with it evenly
Bake in the oven for 30-35 minutes. Cover with tin foil if starts browning too quickly
Serve with high-protein greek style yoghurt for a balanced breakfast
