Well,
a first rule of thumb for picnics and potlucks is don't bring any dish
containing: corn, tomatoes, potatoes, capsicum, peanuts or chocolate.
That is because all of these ingredients are “new world” foods
and, although they may have made it back to Europe within the SCA's
period, in general they just were not eaten.
Super easy and inexpensive dishes to make:
Leek
Soup
Rice
pudding
Mushrooms
and leeks
Apple
pie
Pears
in Red Wine (Pears in Confyt)
Offella (Italian cheesecake pastries)
Easy but fancier dishes to make:
Honey and saffron tart (Doucettes)
Brie
tart
Veal
stew
Salmon
poached in beer
Roast
meat (note, generally in period meat was boiled then roasted)
Hedgehogs
Ravioli
Bizcochos (Spanish Biscotti)
Marzipans for invalids (if you are feeling brave)
Slightly more complex dishes
Oranges of Xativa (Spanish donuts)
Dishes you can buy to bring:
A
cheese platter
Antipasto
(see rule of thumb)
Meat
pie
Nuts (see rule of thumb)
Pork
pie
Dolmades
Cold
meats
Strapped for cash?:
Bread
an
apple pie
Fresh
fruit
Salad
ingredients (see rule of thumb)
peas
beans
Roast
chicken