Preheat oven to 350 degrees. Grease a 13x9 inch baking pan with shortening, set aside.
Place the 2/3 cup butter and 1/2 cup whipping cream in a heavy duty sauce pan over low heat. Stir and cook until butter has melted. Remove from heat, set aside. Combine the flour, baking powder and salt in a small bowl, whisk to combine, set aside.
Place the sugar,vanilla and eggs in a large bowl. Beat on medium speed until mixture is creamy, scraping bowl as you beat. Add the melted butter/whipped cream mixture along with the flour mixture to the bowl. Beat until incorporated. Spread the batter into the prepared pan, bake 30 - 35 minutes until tests done with a toothpick.
Heat your broiler
Combine all topping ingredients in a medium bowl. Stir until well combined. Spread over the warm cake, broil 2 - 4 inches from heat. Broil until topping is bubbly all over, about 4 minutes. Cool the cake about 15 minutes, serve warm or cooled. Top with ice cream if desired.