Preheat oven to 350°F. Grease a 9×5-inch loaf pan with butter or cooking spray and set aside.

In a large bowl, whisk together the buttermilk, mayo, and eggs until combined.

In a separate bowl, whisk together 2 1/2 cups flour, baking soda, baking powder, and salt. Make a well in the center of the bowl and then add the wet ingredients along with the melted butter. Stir with a wooden spoon until the mixture comes together. Turn out onto a floured work surface and knead in as much of the remaining flour as needed to form a smooth, non-sticky, dough. Cover with a towel and set aside.

To make the filling, place the cream cheese, cheddar, parsley, chives, and a pinch of salt and pepper in the food processor. Pulse until smooth.

Divide the the dough into 9 even portions. Roll out each piece roughly into 4×8 inch rectangle. Divide the cream cheese mixture evenly among each piece and spread out evenly. Fold the dough over in half (short side to short side) and place in the prepared pan, stacked close together, opening seam facing down.

Brush the dough with extra buttermilk and sprinkle the top liberally with everything bagel seasoning. Bake until golden brown, or a skewer inserted in the middle comes out clean, about 1 hour. Remove from the oven and allow to cool in the pan for 10 minutes. Remove the loaf from the pan and allow to cool completely.

Serve toasted, with smoked salmon, tomatoes, red onion, cucumber, capers and/or cornichons. Enjoy!