Place the oven rack in the center and preheat oven to 350° F/175° C.
In the small mixing bowl, whisk together flour, nuts (if using), baking powder, baking soda, and salt. Set aside.
In the bowl of the stand mixer, beat the butter and sugar together on medium speed until it's light and fluffy, about 3 minutes. Add the eggs one at a time, beating for 1 minute after each addition. Beat in the vanilla and the almond extract (if using).
Reduce mixer speed to low and add the flour mixture and buttermilk, alternating 1/3 flour mixture, 1/2 buttermilk, 1/3 flour mixture, 1/2 buttermilk, and remaining flour mixture. Mix just until the ingredients are incorporated and scrape down the bowl as needed.
Using a rubber spatula, fold in the chopped apples and prunes (or other fruits). Take care to not over mix.
Scrape the batter into the prepared bundt pan and smooth the top with the spatula.
Bake in the preheated oven for 60 to 65 minutes, or until a thin knife inserted deep in the center comes out clean.
Remove cake from the oven and cool on a wire rack for 10 minutes, then unmold onto the rack and allow to cool to room temperature. Dust the top with confectioners sugar for serving. Cake will keep for up to 5 days at room temperature or 2 months in the freezer wrapped well in plastic.