  We introduce a protocol that gives access to out-of-time-ordered correlation
functions in many-body quantum systems. Unlike other such protocols, our
proposal, which can be applied to arbitrary initial states, neither requires
ancilla degrees of freedom to the quantum system of interest, nor has the need
for randomized measurements. Nontrivial experimental capabilities required to
implement the protocol are single-site measurements, single-site rotations, and
backwards time evolution. To exemplify the implementation of the protocol, we
put forward a strategy for Hamiltonian sign inversion $H\to-H$ in arrays of
Rydberg-dressed atoms. In this way, a complete and practical toolbox is
obtained for the measurement of out-of-time-ordered correlations in equilibrium
and nonequilibrium situations.
