Spice Cake with Maple Syrup Italian Buttercream (VIDEO)

Measurements below:

Spice cake (Two 8-inch cake layers)

4 cups flour (480g)
6 teaspoons pumpkin pie spice mix (10g)
(To make spice mix: cinnamon (5.5g), nutmeg (1.5g), ginger (1.5g) cloves 1.5g)
4 large eggs
2 cups brown sugar (360g)
1C granulated sugar (195g)
2 sticks butter (226g)
2 tsp soda (4g)
1 tsp powder (2g)
2 TB vanilla (23g)
2.5-3 C buttermilk (600g)
1 tsp salt (5g)

Maple Syrup Italian Buttercream
IMPORTANT NOTE: Bring cooked sugar up to 235F/113C, NOT 135F/57C

1lb butter (4 sticks) (452g)
2C brown sugar (380g)
1/2C water
6 egg whites (240g)
2/3C maple syrup (220g)

Simple syrup:

1:1 ratio water to granulated sugar