Put the oats and walnut into a food processor and whiz until you get coarse crumbs. Add the yogurt/cream, the banana, maple syrup, baking powder and flaxseed, then whiz again. You should get a thick batter. If time allows, rest for 30 minutes or so.
Oil a pancake pan and add dollops of the batter. Using the base of the spoon, flatten them down into patties. Cook for a couple of minutes, then turn them over.
Repeat with the remaining batter.
Serve warm with maple syrup and walnuts or custard/yogurt. Alternatively, let them cool and snack on them during the day.