Sift the flour and baking powder into a bowl and then add the salt, stir to combine.
Place the sugar, eggs and vanilla bean paste in a large bowl and whisk together until it's lighter in colour and emulsified together.
Add the dry ingredients to the egg mixture in two batches, whisking until fully mixed each time.
Take the melted butter and pour it into the batter, whisking at the same time, keep whisking until the butter is fully incorporated.
Add the lemon juice and whisk until it is fully mixed in. Then add the zest and poppy seeds and fold in gently so you don't knock out any air in the muffin mix.
Transfer the batter to an airtight container and put a lid on it and place it in the fridge overnight or for up to 36 hours.
The next day to make the muffins, pre-heat the oven to 220C Fan and place the panettone cases on a baking tray.
Place 130g of batter in each panettone case, the easiest way to do this is place your case on a digital scale, set it to 0 and then add the batter until it reaches 130g. Place the cases on a baking tray.
When you have filled all 6 cases, place them in the oven and immediately drop the temperature to 170C Fan and bake for 30 mins or until a skewer inserted comes out clean.
When they are cooked place them on a cooling rack, they are best eaten on the day they are baked but will keep well for a couple of days in an airtight container.