Baked mücver courgette feta bake

Name: Baked mücver (courgette & feta bake)
Ingredients: 6 courgettes (about 325g); 2 spring onions, finely sliced; ½ small bunch of parsley, finely chopped; ½ small bunch of mint, finely chopped; ½ small bunch of dill, finely chopped, plus extra to serve; 4 eggs; 75g grated halloumi; 100g crumbled feta; 2 garlic cloves, grated; 4 tbsp olive oil, plus extra for the tin; 80g plain flour; 1 tsp baking powder; 1 tbsp toasted sesame seeds, plus extra to serve; 1 tbsp nigella seeds, plus extra to serve