Rhubarb Madeleines Upside Down Cake - Donsuemor

Ingredients

• 1 cup all-purpose flour
• 1/2 cup (3 Madeleines), ground to a fine crumb
• 1 teaspoon baking powder
• ½ cup unsalted butter
• 1 cup white sugar
• 5 eggs
• ½ teaspoon vanilla extract
• 3 cups sliced fresh or frozen rhubarb
• 1 cup sugar
• 2 tablespoons all-purpose flour
• 1/4 teaspoon ground nutmeg
• Tbsp of lemon, and lemon zest
• 2 Tbsp cup butter, melted