You could point her towards the verse in the Acts of the Apostles, where a link between Eucharist and Apostolic activity is found:
“They devoted themselves to the teaching of the Apostles, prayers and the breaking of the bread”.
Here the “breaking of the bread”, which the Church has always interpreted as the Eucharist, seems to overshadow the “sharing of the cup”.
Likewise, another key Eucharistic passage in the New Testament is found in Luke 24: 28-35.
Here Jesus, with the disciples on the road to Emaus, only blesses, gives thanks, breaks, and distributes the bread. Here the the Lord is recorded as being “made known to them in the breaking of the bread”- clearly Eucharistic, yet with no mention of the cup,