And they were continually devoting themselves to the apostles' teaching and to fellowship, to the breaking of bread and to prayer.Day by day continuing with one mind in the temple, and breaking bread from house to house, they were taking their meals together with gladness and sincerity of heart.
Acts 2:42,46

Now when evening had come, Jesus was reclining at table with the twelve disciples. And He said to them, “I have earnestly desired to eat this Passover with you before I suffer; for I say to you, I shall never again eat it until it is fulfilled in the kingdom of God.” And as they were eating, He said, “Truly I say to you that one of you will betray Me -- the hand of the one betraying Me is with Me on the table.” And being deeply grieved, they each one began to say to Him, “Surely not I, Lord?” And He answered and said, “It is one of the twelve, one who dips his hand with Me in the bowl is the one who will betray Me. “The Son of Man is to go, just as it is written of Him; but woe to that man through whom the Son of Man is betrayed! It would have been good for that man if he had not been born.” And Judas, who was betraying Him, answered and said, “Surely it is not I, Rabbi?” He said to him, “You have said it yourself.” And while they were eating, Jesus took some bread, and after He blessed it, He broke it and gave it to the disciples, and said, “Take, eat, this is My body.” And He took a cup, and when He had given thanks, and gave it to them, saying, “Take this and share it among yourselves; drink from it, all of you; for this is My blood of the covenant, which is to be shed on behalf of many for forgiveness of sins. “Truly I say to you, I will not again drink of this fruit of the vine until that day when I drink it new with you in My Father's kingdom.” And after singing a hymn, they went out to the Mount of Olives.
from Matthew 26:20-30; Mark 14:18-26; Luke 22:14-22.

Is not the cup of blessing which we bless a sharing in the blood of Christ? Is not the bread which we break communion in the body of Christ? Since there is one bread, we who are many are one body; for we are all partaking of the one bread.
I Corinthians 10:16-17

For I received from the Lord that which I also delivered to you, that the Lord Jesus in the night in which He was betrayed took bread; and when He had given thanks, He broke it, and said, “This is My body, which is [broken] for you; do this in remembrance of Me.” In the same way He took the cup also, after supper, saying, “This cup is the new covenant in My blood; do this, as often as you drink it, in remembrance of Me.” For as often as you eat this bread and drink this cup, you proclaim the Lord's death until He comes.
I Corinthians 11:23-26

But as touching the eucharistic thanksgiving, give thanks thus. First, as regards the cup: We give You thanks, O our Father, for the holy Vine of Your son David, which You made known unto us through Your Son, Jesus; Yours is the glory for ever and ever. Then as regards the broken bread: We give You thanks, O our Father, for the life and knowledge which You did make known unto us through Your Son, Jesus; Yours is the glory for ever and ever. As this broken bread was scattered upon the mountains and being gathered together became one, so may Your Ekklesia/Edah be gathered together from the ends of the earth into Your Kingdom; for Yours is the glory and the power through Jesus Christ for ever and ever. But let no one eat or drink of this eucharistic thanksgiving, but they that have been baptized into the name of the Lord.
Didache 9:1-10

The celebration of which our Lord Jesus Christ prescribed, in remembrance of the suffering which He endured on behalf of those who are purified in soul from all iniquity, in order that we may at the same time thank God for having created the world, with all things therein, for the sake of man, and for delivering us from the evil in which we were, and for utterly overthrowing principalities and powers by Him who suffered according to His will.
Justin Martyr Dialogue with Trypho 41:1

And this food is called among us Eukaristia [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transformation are nourished, is the flesh and blood of that Jesus who was made flesh. For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, “This do in remembrance of Me, this is My body;” and that, after the same manner, having taken the cup and given thanks, He said, “This is My blood;” and gave it to them alone.
Justin Martyr First Apology 66:1

Unleavened Bread Recipe: Mix all ingredients and leave to rest for at least half an hour. Then take small portions (egg size) and role out thinly on a floured board to about the size of a tea plate. Place under a hot grill till the cakes blister - approximately 2 to 3 minutes. Turn and grill the other side and they are ready to serve. If no grill is available, these can be cooked on a hot plate or frying pan. Those who are allergic to wheat flour may use other flour: rye, barley, maize, oats or millet etc. To avoid natural fermentation it is advisable to daily mix a fresh batch of dough.

Unleavened Bread?

Clean out the old leaven, that you may be a fresh/new lump, just as you are in fact unleavened, uncontaminated. For Christ our Passover Lamb also has been sacrificed for our sakes so that we may be feasting, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of honor, sincerity and unadulterated truth.
I Corinthians 5:7-8