Pre-heat the oven to 160 degrees, fan bake.Grease two 20 cm sponge or cake tins with butter and line with baking paper on the base and up the sides. Add the pata (butter) to a medium size pot and melt over medium heat. Continue heating until the pata (butter) is foamy and brown bits float to the top, stirring occasionally. Keep it on the heat (for an extra 30 seconds) until it smells nutty.
Remove from the heat, pour in to a small bowl and leave to cool.
Separate the hēki (eggs). Add the tōhua hēki (egg yolks) in to a large bowl and the kahu hēki (egg whites) in to a medium bowl.
Add the first measure of huka one (caster sugar), wanira (vanilla) and tote (salt) in to the bowl of tōhua hēki (egg yolks). Whip it all on high for 3 minutes until thick, fluffy and pale in colour. Sift in the peru oneone (almond meal), puehu kānga (cornflour) and pēkana paura (baking powder). Fold it together. The mixture will be quite tight at this stage but trust me, it will be ok!
Add the second measure of huka one (caster sugar) in to the kahu hēki (egg whites) that you prepared earlier. Whip it for 3 - 4 minutes on medium-high until stiff peaks form. Add a third of the tāhungahunga (meringue) in to the egg yolk mixture. Fold it in and watch as the mixture beings to loosen.
Add another third of the tāhungahunga (meringue) and fold it in.
Drizzle in half of the cooled pata parauri (brown butter) around the edge of the bowl, folding until it is incorporated. Add the second half of the pata parauri (brown butter) and fold it all together.
Add the final third of the tāhungahunga (meringue) and fold it in.
Divide the mixture between the two prepared tins and spread it out evenly.
Bake for 30 minutes.
As soon as you remove the sponges from the oven, pull the baking paper off the edge of the cakes before it cools. This helps the cakes keep their shape.
Remove them from the tins after cooling for 5 minutes and transfer to a cooling rack. Leave them to cool for 20 minutes. These can also be made a day ahead and kept in a sealed container in the cupboard until needed.