What was served in Jesus' last supper?
You get somewhat of a clue when Jesus gives the disciples communion. They had wine and unleavened bread (without yeast).
As this was a Passover Seder meal observance, the following would have been served, as a minimum:
Matzah - unleavened bread.
Maror and Chazeret - two sorts of various bitter herbs....possibilities include lettuce, endive, pepper grass,or watercress.
Karpas - a vegetable dipped in salt water and vinegar.
Z'roar - roasted lamb shank.