Preheat oven to 300F
Line an 8x8 baking dish with parchment paper across both directions so there is an overhang.
Sift and whisk the dry ingredients together.
In a separate bowl, beat the eggs until light yellow and fluffy (approx 3 minutes at medium speed)
Slowly add the dry ingredients to the eggs, and keep beating on low speed.
Slowly add the butter and vanilla extract, and keep beating on low speed.
Pour the batter into the pan and bakefor 15 minutes.
Remove from heat for 15 minutes.
Return to oven and bake until internal temp reaches 195F (approx 30 minutes)
Cool for 30 minutes in the pan.
Remove and let cool another 10 minutes on cooling rack.