Start by taking a 12-inch iron skillet and melting 1½ stick of butter. Next, go ahead and add in the brown sugar, stirring constantly until it starts to bubble and is well-combined.

Next, put the blackberries and peaches over the brown sugar mixture in your skillet or pan. Set aside.

Start by blending together the flour, baking powder, and granulated sugar. Once done, set aside.

Next, you're going to mix in 1½ sticks butter on medium speed until it's nice and fluffy.

Once that is done, take and add in the eggs, one at a time, one low speed after you add one.

Take your dry ingredients and add them to wet ingredients. Mix on medium speed until well combined.

Take and pour the cake batter over the fruit in the pan and put on the center rack of your preheated oven.

Bake for about 55 minutes, or until golden brown and toothpick inserted into the center comes out clean.

Take the cake from the oven. You can loosen the cake by running a knife around the edges and once you do, immediately dump the cake over onto a serving platter.