Preheat oven to 350 degrees F. Coat the bottom and sides of an 8 inch round cake pan with 2 tablespoons of the butter. Use all the butter to thickly coat the pan.

Evenly sprinkle ½ cup of granulated sugar on the bottom of the baking pan. Sprinkle ½ teaspoon of cinnamon and the nutmeg evenly over the sugar.

Arrange the raspberries and blueberries in a single layer over the sugar. Set aside.

Using and stand mixer or a hand mixer, beat the remaining 6 tablespoons of butter with the remaining ½ cup sugar for 2 to 3 minutes.

Add the egg and vanilla extract and beat for 1 minute.

In a small bowl, combine the all purpose flour, the remaining ½ teaspoon of cinnamon, baking powder, and kosher salt.

With the mixer on low speed, alternately add the flour mixture and ½ cup heavy cream in 2 batches. Mix until just combined.

Add the batter to the baking pan and carefully spread it evenly over the berries.

Place the pan on a parchment paper lined baking sheet and bake for 30 to 40 minutes. The cake is done when a toothpick is inserted and comes our clean.

Remove the cake from the oven and place on a cooling rack for 15 minutes.

Loosen the cake by running a knife around the edges. Carefully flip the cake over on a serving dish or cake stand.

Using a stand mixer or hand mixer, beat the remaining 1 cup of heavy cream until it has soft peaks.

Cut the cake into wedges and serve with the whipped cream.