Preheat oven to 200C. Place bread halves, cut-side up, on an oven tray. Drizzle with 2 tablespoons oil and season with salt and pepper. Bake for 10 minutes or until golden and toasted.

Meanwhile, heat remaining 1 1/2 tablespoons oil in a large, non-stick frying pan over low–medium heat. Add onion and 1/2 teaspoon salt, and cook, stirring occasionally, for 8 minutes or until soft. Add 2 teaspoons lemon juice, stir to combine, then transfer to a bowl. Wipe pan clean and reserve.

Line a large tray or work surface with a sheet of baking paper. Heat 15g butter in reserved pan over low–medium heat. Crack in 2 eggs and fry for 2 minutes or until whites are set but yolks are still runny. Using a spatula, carefully transfer eggs to prepared tray. Repeat twice more with butter and remaining eggs.

Place toasted bread halves on a large platter or chopping board, spoon 3 mounds of yoghurt at intervals along each piece, then divide onions among mounds. Place eggs near each mound.

Return frying pan to medium heat. Add remaining 105g butter, garlic and cumin, and cook, stirring, for 1 minute or until fragrant. Add remaining lemon juice, season with salt, then cook for 1 minute or until sizzling.

Drizzle butter mixture over eggs, then scatter with chilli flakes and mint. Cut each bread half into thirds and serve immediately.