Add butter and sugars to a mixer and cream together until light and fluffy. Mix in Greek yogurt.

Add pumpkin, eggs and vanilla and mix.

In a separate mixing bowl, stir together flour, baking soda, salt, cinnamon, ginger and nutmeg.

Mix the dry ingredients with the wet.

Pour batter into a jelly roll pan (10x15 inch). Bake at 350 degrees F for about 27-30 minutes, or until a toothpick inserted in the center comes out clean.

As soon as the cake comes out of the oven, make the frosting.

In a medium saucepan, combine the butter, cream, brown sugar and salt, and cook over medium heat, stirring constantly, until the mixture comes to a gentle boil.

Remove from the heat and stir in vanilla and 2 cups powdered sugar. Mix well (I like to use an electric mixer to remove any lumps).

Add a little extra powdered sugar, as needed, until you get a soft and slightly thick, but pourable frosting.

Gently spread warm frosting over bars. Allow to cool before serving.