Take a small, heavy-bottomed pot and mix it with 1 1/2 cups sugar and 1/2 cup water

Boil it over high heat and cook for about 5-7 minutes without stirring till the syrup is gently
bubbling all across surface

Remove from the heat and add 8 Tbsp. butter in small pieces and stir

Now take a 9” cake pan and pour the resulting caramel

Cut sweet potatoes into very thin slices using a mandoline or knife

Now arrange the sweet potatoes in concentric circles starting in center of cake pan

Each piece should overlap over half of previous piece

Now circle the sweet potatoes out to edge of pan and then back toward center until there are 2 layers

Spoon the top with 2 Tbsp. water

Now preheat the oven to 350° and place a rack in the center

Take a large bowl and stir the remaining 3/4 cup sugar, baking soda, flours, nutmeg, salt, cinnamon and all spice and keep it aside

Now melt the remaining butter

Take another bowl and stir together vanilla, yogurt, melted butter and egg

The butter mixture should be added to flour mixture and stirred to combine

Spoon batter over arranged sweet potatoes

Smoothing batter to edges of the pan

Now start baking rotating the pan halfway through till the cake is golden brown

Spring it back lightly around 50 to 55 minutes

Allow it to cool for 5 minutes and then place a plate on pan

Invert the whole arrangement flipping the cake onto plate

Allow it to cool slightly before serving