How to Make It
Preheat the oven to 350°. Butter and flour a 9-inch-square cake pan. In a heatproof bowl, soak the oats in the boiling water for 20 minutes. Drain well.
In a medium bowl, sift the flour with the baking soda, cinnamon, nutmeg and salt. In a large bowl, using a handheld electric mixer, beat the butter until creamy. Add the brown and granulated sugars and beat until light and fluffy. Beat in the eggs, 1 at a time, then beat in the vanilla. Add the soaked oats and beat at medium speed just until combined. At low speed, beat in the dry ingredients.
Scrape the batter into the prepared pan and bake the cake in the middle of the oven for 40 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool in the pan for 10 minutes. Turn the cake out onto a wire rack, then invert it and let cool completely.
Cut the cake into squares and serve with the Warm Mixed-Berry Compote and clotted cream.