We report the realization and investigation of a ballistic Andreev interferometer based on an InAs two dimensional electron gas coupled to a superconducting Nb loop. We observe strong magnetic modulations in the voltage drop across the device due to quasiparticle interference within the weak-link. The interferometer exhibits flux noise down to $sim 80, muPhi_0/sqrt{textrm{Hz}}$, and a robust behavior in temperature with voltage oscillations surviving up to $sim7,$K. Besides this remarkable performance, the device represents a crucial first step for the realization of a fully-tunable ballistic superconducting magnetometer and embodies a potential new platform for the investigation of Majorana bound states as well as non-local entanglement of Cooper pairs.
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