Preheat oven to 350 degrees. Grease and flour a 9x13 inch sheet pan or 2 round cake pans.
Whisk together the flour, baking powder, baking soda, salt, and spices. In a separate large bowl, combine sugar and oil. Stir in yogurt, vanilla, and pumpkin. Beat eggs in one at a time, mixing very well after each addition.
Gradually add the flour mixture to the wet ingredients. Spread batter into prepared pans. Bake for 40-50 minutes. Cool completely.
While that’s happening, melt the chocolate chips and allow the chocolate to cool a bit. You can also use bittersweet or dark chocolate, but if you do, we suggest adding a tablespoon of powdered sugar to the cream. Whisk together the heavy cream, cocoa powder, cinnamon and chili powder. Whip for about 5 minutes, or just until the cream reaches the “stiff peaks” stage. In a large bowl, carefully fold about half of the cream into the chocolate. Then fold in the remaining cream.
When the cake is completely cool, layer the cream in the middle and on top of the cake. Garnish with chocolate shavings.