Erin Patterson has conceded she added foraged wild mushrooms and made "deviations" to a beef Wellington that would allegedly kill three of her former in-laws.
The 50-year-old gave evidence for a third day in her Supreme Court trial in regional Victoria.
She has pleaded not guilty to three murders and one attempted murder over the July 2023 lunch she served to Don and Gail Patterson, 70, and Gail's sister Heather Wilkinson, 66.
All three died in hospital days after eating the meals, while Heather's husband Ian Wilkinson was the sole surviving lunch guest.
Patterson, who maintains the poisonings were not deliberate, revealed on Wednesday the steps she took to make the beef Wellington dish.
A majority of the ingredients were bought from Woolworths, including mushrooms, eye fillet steaks, filo pastry, potato mash, green beans and puff pastry, she told the jury.
Patterson made "deviations" to the RecipeTinEats recipe, including buying 10 beef tenderloin steaks after being unable to find a log of beef, swapping in filo pastry instead of making a crepe and omitting mustard and prosciutto because Ian didn't eat pork.
She recalled starting quite early on the day of the lunch by frying up garlic and chopped shallots before adding two tubs of mushrooms she bought from Woolworths to make the duxelles, or the mushroom wrapping.
"I cooked it down. I tasted it a few times. It seemed bland so I decided to add the mushrooms from the grocer I had in my pantry," she told a full courtroom and 14 jurors.
Defence barrister Colin Mandy SC asked her to reflect on what may have been in the container of mushrooms from the pantry, which she said she bought from Melbourne.
"Now I think that there was a possibility there were foraged ones in there as well," she responded.
Patterson previously said she started foraging for wild mushrooms during the COVID-19 pandemic in 2020 at Korumburra Botanic Gardens, on her 1.2 hectare properties in Korumburra and Leongatha, and along a rail trail leading out of Leongatha.
Leongatha is in south-east Victoria, about 130km from the Melbourne CBD.
Mandy asked Patterson "do you accept there must have been death cap mushrooms" in the lunch she served to her former husband's family, to which she said yes.
Patterson recalled making six beef Wellington parcels, ensuring they would be done and resting out of the oven by 12.30pm when her guests arrived.
Victoria Police detective senior constable Stephen Eppingstall (rear left, in suit) and Ian Wilkinson (right, in dark jumper and light-coloured trousers) arrive at the Latrobe Valley Magistrates Court in Morwell, Victoria. Source: AAP / James Ross
Patterson recalled Ian, Don and Heather finishing their entire plates, Gail eating "quite a lot of hers, not all" which Don finished, and that she ate about a quarter to a third of her own plate.
"I was talking a lot. I was eating slowly," she said.
Her in-laws left because Ian had a meeting at his church and left Patterson to clean up the kitchen and put things away, admitting she had the rest of the cake Gail had brought.
"I felt sick. I felt over-full. So I went to the toilet and brought it back up again," she said.
Patterson recounted feeling a bit better, with only symptoms of loose stools that afternoon and evening.
Her evidence will continue on Wednesday.
Lines of people curious to catch a glimpse of Patterson giving evidence have stretched from the regional court's doors as the trial continues into its sixth week.
