It’s my belief that she will have sprinkled the Death Cap powder into the mushroom mixture of each of 5 of the Pies, leaving the remaining mushroom mixture free of toxins.
If my memory serves me correctly, Ian said they were ‘encased in pastry’.
I suggest she :
Made a big batch of the sautéed mushroom mixture, it takes a while to dry right down
Cut off a piece of the fillet steak to use for the next night’s dinner with the kids
Then seared the remaining piece of fillet
Cut the fillet into 6 slices
Maybe she pasted some mustard over the beef
Prepared 6 sheets of thawed puff pastry - sitting 1 sheet off to the side
The prep for 5 of them possibly involved a tablespoon or 2 of mushroom mixture in middle of each sheet of pastry
Sprinkle a liberal amount of powdered DC over each
Top mushrooms with fillet steak, then a tbsp of mushrooms, a good seasoning of DC
and top with a final tbsp of mushroom mixture.
Bring up the sides of the puff pastry & seal on top. Egg wash - and admire.
Finally prep # 6 sitting off to the side - same steps Except no DC seasoning (none left anyway)
And just to be doubly sure, I’d Mark the Top of this one
Then into the oven they go.