Stir the warm water, yeast and 1 teaspoon of maple syrup in to a jar together. Leave in a warm place to "bloom" for 5 minutes. You'll know the yeast has bloomed when the mixture looks frothy. If it does't froth you'll need to buy fresh yeast.
In a large bowl combine the flour, baking powder and salt. Mix together and create a well in the centre.
Pour in the yeast mixture, the remaining teaspoon of maple, 2 tablespoons of melted butter, yoghurt and nigella seeds.
Stir together first and then start to bring the mixture together with clean hands. If the mixture is super wet, add a tablespoon of flour; too dry add a tablespoon of water. The dough should be very soft but not so wet that it won’t come together in a ball.
Knead the dough until smooth and elastic. This will take around 10-minutes by hand on a lightly floured surface or around 6-minutes in a mixer. Add a touch more flour at a time - no more than a teaspoon - if the dough is too sticky.
Form the dough in to a ball and pop it in to a lightly greased larger bowl. Cover with cling film or a clean tea towel and place the bowl in a warm spot for at least an hour to double in size. After it has doubled cut it in to 6 - 8 equal-ish balls. I cut mine in to 8 - I think that's plenty big enough.
Pop a cast iron skillet over medium heat.
Lightly flour your rolling pin and roll each ball in to a flat-ish round around 10-12cm wide. Pro Tip: You can lightly brush the top with a touch of water to make sure the bread doesn't stick to your pan.
Gently lay the naan on the skillet, wet side down.
Cook for around 2 minutes or until bubbles begin to appear on top of the naan. If you peek under the naan and the underside is getting too dark, turn the heat down.
Flip the naan and cook the other side for a minute or so.
Remove the naan from the pan and brush with the melted butter and sprinkle with sea salt to serve. Repeat with the remaining naan breads. Enjoy!