Preheat oven to 350 degrees F (180 degrees C). Grease a loaf pan.
Wash the Wineberries (1/2 cup) and Blackberries (1/2 cup) and set aside.
Zest the Lemon (3).
In the bowl of a stand mixer, combine Unsalted Butter (1/2 cup), Granulated Sugar (1 cup) and lemon zest.
Cream until light and fluffy.
Add Egg (3), one at a time, beating well after each one.
In another bowl, whisk together Unbleached All-Purpose Flour (2 cup), Baking Powder (1 1/2 teaspoon), and Salt (1/2 teaspoon). After scraping down the sides of the bowl, alternate between the dry ingredients and Plain Yogurt (1 cup).
Once the dry and wet ingredients have been fully incorporated, carefully fold the berries into the lemon zest flecked batter. Pour the batter into the prepared pan.
Bake for 60 to 65 minutes or until a toothpick inserted in the middle comes out clean.
For the glaze, mix the Powdered Confectioners Sugar (1 cup) and Lemon (2 tablespoon).
Let cool on a wire rack for 10 minutes and then turn out and cool completely before drizzling with glaze.