1 cup rolled oats
1 1/4 cups boiling water
1 1/2 cups all-purpose flour
1 teaspoon baking soda
1/2 teaspoon salt
3/4 teaspoon cinnamon
1/4 teaspoon nutmeg
1/2 cup (1 stick) unsalted butter
1 cup sugar
1 teaspoon vanilla extract
1/4 cup (1/2 stick) unsalted butter, melted
1/2 cup brown sugar
3 tablespoons heavy cream
3/4 cup shredded coconut
Powdered sugar, optional
Preheat oven to 350º F and lightly grease an 8×8-inch baking dish with butter or non-stick spray.
Place oats in a heatproof bowl and pour boiling water over them. Set aside to let soak for 20 minutes.
In a medium bowl, whisk together flour, baking soda, salt, cinnamon and nutmeg and set aside.
In a large bowl or mixer, cream together butter and sugar for 2-3 minutes, or until fluffy and lightened in color, then beat in eggs and vanilla extract.
Fold soaked oats into egg mixture, then mix in dry ingredients until incorporated and smooth.
Pour batter into greased baking dish and bake for 40-50 minutes, or until toothpick inserted in center comes out clean.
While cake bakes, mix melted butter, brown sugar, cream and shredded coconut together.
Remove cake from oven and pour topping evenly over the top, then return cake to oven and broil for 2-4 minutes, or until bubbly and golden.
Remove from oven and let cool at least 10-15 minutes before serving.