6 Tbsp. unsalted butter cut into cubes (at room temperature), plus more for buttering the loaf pan
4-1/2 cups All-purpose flour, plus more for shaping the dough
2 tsp. Fine sea or kosher salt
Vegetable oil, for the bowl
FOR THE FILLING:
4 Tbsp. melted and cooled unsalted butter, plus more for the pan and finishing
8 ounces Cooked bacon, drained, cooled, and crumbled
1-1/2 cups Shredded Sharp Cheddar Cheese
1/2 cup Grated parmesan, plus more for finishing
1 can Pearls California Ripe Black Sliced Olives, drained
1 Large egg, beaten
Place the warm water in the bowl of a stand mixer and sprinkle the yeast over it. Let stand 10 minutes until dissolved and slightly foamy.
When the yeast is ready, add the milk, sugar, eggs, softened butter, flour, and salt. Use the dough hook to stir the mixture on medium-low until combined, then knead on low 5-6 minutes until the dough is smooth and elastic, adding more flour by the tablespoon if needed to make the dough come away from the sides of the bowl.
Turn the dough out onto a lightly floured surface, shape into a ball, and place in a large bowl coated lightly with vegetable oil. Cover the bowl and let rise in a warm place until doubled or tripled in bulk, 1½ to 2 hours.
Turn the risen dough out onto a lightly floured surface, divide in half, form each half into a ball, and place on a baking sheet lined with parchment paper. Cover with a clean kitchen towel and let rise again until doubled in bulk, 45-60 minutes.
While the dough rises for the second time, prepare the filling ingredients. Butter a 9x5-inch loaf pan with soft butter, line it on all sides with parchment paper, and butter the parchment paper.
Position a rack in the middle of the oven and preheat to 400ºF.
When the dough has risen, keep one dough ball covered and roll the second ball out on a lightly floured surface to a 12x15-inch rectangle. Cut each rectangle in thirds each way to form 9 smaller 4x5-inch rectangles. Repeat with the second dough ball.
Brush the dough rectangles with the melted butter, and sprinkle each with the cheeses, bacon, and olives. Stack three rectangles on top of each other and repeat with the remaining squares. Stand the rectangles upright in the prepared pan until the pan is filled. Brush the top with the beaten egg.
Bake the bread for 30-35 minutes until golden brown. Brush with more melted butter. Remove from the pan and let cool 20-30 minutes before serving. Serve warm or at room temperature.