Final answer:
The question about the farmhouse burger's new bun type does not align with an academic subject and cannot be answered without specific information from the restaurant in question.
Step-by-step explanation:
The question about the type of bun the farmhouse burger will now be served on does not pertain to any academic subject but rather to a specific restaurant's menu item.
The information needed to answer this question is not provided. If this question relates to a real-life change in a restaurant's offering, one would need to check the menu of that particular establishment or contact them directly for the most accurate and updated information.