Preheat the oven to 350°F (175°C).
In a mixing bowl, combine yogurt, honey (or maple syrup), olive oil, and eggs. Whisk until well blended.
In another bowl, whisk together whole wheat flour, baking powder, and salt.
Gradually add the dry mixture to the wet ingredients, stirring gently until just combined.
Fold in the optional berries or nuts if using, then pour the batter into a greased cake pan.
Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
Remove from the oven and let the cake cool in the pan for about 10 minutes before transferring to a wire rack.
Slice and serve once cooled; enjoy your healthy yogurt cake!