I don't know where you live but if you have not already done so, check quietly about the health department regs on preparing food to be sold; state licenses, regs and labeling requirements for food manufacturing, and your municipal regulations on zoning for commercial food prep.

If possible, the safest way to deal with this is to get time at an already licensed facility- a restaurant or bakery after hours, church kitchen, etc. Some areas have small business support projects (gov funding) to help people find out if they can get a stable market for the product before investing hugely in their equipment.

That saud, it depends on what kind of volume you are aiming for. A Hobart mixer- 30 quart- can be found second hand and is great for a starter. A really good over matters, and convection electric is more even-heating in the home sizes. A rolling oven, like a pizza oven is used by many larger companies

If you have not ever run a food business, consider taking some workshops on starting the business with the local federal Small Business Asministration/ Service Corps of Retired Executives before you go much further into the business. A customer can break a tooth or bridge on a biscotti, and you need to know about liability issues BEFORE you need to know about liability issues.