Put the walnuts into a small food processor and blend into a coarse mixture. Transfer it to a big mixing bowl, then add the yoghurt and eggs. Mix well, then fold in the flour, cinnamon and oil. Combine until you get a smooth, thick put pourable batter. Set aside to rest.
Make the pear topping. Peel the pears, remove the core and slice them into long, thin wedges. Put them in a non-stick saucepan, add the butter, sugar and cinnamon. When melted, put the pear slices into the butter, and squeeze some lemon juice over them. Cook for about 5-10 minutes, until the pear slices are sticky and lightly caramelised all over. Turn off the heat and keep them warm.
Meanwhile heat the waffle maker. Once it’s hot, spoon in some batter, seal the machine and cook for about 5 minutes, until golden. Transfer to a plate or wire-rack, then repeat. You can make about 4 waffles, depending on your waffle maker. Keep them warm.
Serve the waffles with the caramelised pears, drizzled with maple syrup.