She died after suffering an allergic reaction to a meal from the Royal Spice takeaway in Union Road, Oswaldtwistle, on December 30, 2016.
Mohammed Abdul Kuddus, 39, of Blackburn, and 38-year-old Harun Rashid, of Haslingden, denied charges of manslaughter when they appeared at Preston Crown Court.
They are also accused of failure to discharge the general duty of employers and contravention of EU safety regulations, on behalf of the RS Takeaway Ltd trading as Royal Spice.
The two defendants and the company are alleged to have failed to display information regarding allergenic ingredients to consumers; and placed food on the market, namely peshwari naan, onion bhaji and seekh kebab, which contained peanuts and were therefore unsafe.
Kuddus and Rashid were given conditional bail to appear at Manchester Crown Court for a pre-trial review on September 21.
A date for the trial, which is estimated to last three weeks, has been set for October 2. It will take place at Manchester Crown Court before a High Court judge.