Make the Dough

• Combine the flour, sugar, salt and yeast in the bowl of a stand mixer fitted with the dough hook
• Add the eggs, buttermilk, and melted butter
• Mix on medium speed for one minute until combined
• Knead on medium high speed for 10 – 15 minutes until the dough is soft and silky. When you push down on it the dough should feel firm and elastic.
• Transfer the dough to a large, oiled bowl and cover with plastic wrap. Let sit in a warm place until the dough has tripled in size, about 1 1/2 hours.
• to test if the dough is fully risen, make in indentation with your finger in the center of the dough. If the indentation remains, move on to the next step. If not continue to let rise.

Make the streusel topping

• Whisk together the all pupose flour and sugar
• Add the butter and use your fingers to rub it in until you have a breadcrumb like texture.
• Chill in the refrigerator for at least 30 minutes or until ready to use

Form the cake

• Lightly butter a 9 x 13″ pan and line it with parchment paper. Scrape the dough into the pan and smooth it with your hands
• Scatter the berries over the top of the dough
• Cover and let sit at room temperature until it doubles in size about 25 minutes
• Meanwhile, preheat oven to 350
• Sprinkle the streusel over the top of the cake
• Bake for about 35 minutes until a tester comes out clean
• Let cool on a wire rack
• Dust with powdered sugar if desired before serving