Add all the flatbread ingredients to a mixing bowl and mix together with a spoon, then use clean hands to pat and bring everything together.
Dust a clean work surface with flour, then tip out the dough. Knead for a minute or so to bring it all together.
Put the dough into a floured-dusted bowl and cover with a plate, then leave aside.
Melt the butter in a saucepan and add most of the dill, then set aside.
Dust a clean work surface and rolling pin with flour, then divide the dough in half, then divide each half into 6 equal-sized pieces (roughly the size of a golf ball).
Use a rolling pin to roll each piece into very thin rounds, roughly 2mm to 3mm thick.
Place the griddle pan on a high heat, then once hot, cook each one for 1 to 2 minutes on each side, or until bar-marked and puffed up, turning with tongs.
Heat the oven to 200 C. Fry the onion in a spray of oil until soft but not brown, and allow to cool. Drain the lentils well and put in a blender with the cooled onion, mushrooms, oats and lemon zest and chilli. Pulse until the mix is combined (but don’t blend to a mush).
Season, and roll into 14 balls, then put them on a lined baking sheet. Bake for 30 minutes until golden and firm, turning them halfway through.
To make the salad, mix all the ingredients together to combine. Top the flatbreads with the lentil ‘meatballs’, the tomato salad, a dollop of yoghurt and a drizzle of oil.