1/2 c. mayonnaise
3 T. ketchup
2 T. finely chopped dill pickle
Salt and pepper
3 c. grated Swiss cheese
2/3 c. sauerkraut, drained and roughly chopped
4 oz. cream cheese at room temperature
4 oz. chopped sliced pastrami
1 loaf pumpernickel bread
Preheat the oven to 375 degrees. Whisk the mayonnaise, ketchup and pickle in a large bowl until combined; season with salt and pepper.
Add the Swiss cheese, sauerkraut, cream cheese and pastrami to the mayonnaise mixture; stir until combined. Using a small serrated knife, hollow out the bread loaf, leaving a 1/2 inch shell; reserve the cut-out bread. Fill the loaf with the dip; transfer to a baking sheet.
Slice the reserved bread into pieces and arrange on a separate baking sheet; brush or spray with olive oil. Bake the bread bowl until the cheese melts, about 30 minutes. Add the sliced bread to the oven during the last 10 minutes. Serve with toasted bread and crackers and celery sticks.