Witness verifiable quantum advantage
Brakerski, Christiano, Mahadev, Vazirani, and Vidick propose a scheme for verifiable quantum computational supremacy based on a strengthening of trap-door claw-free functions (TCFs).

In the above scheme:


Vicky the classical verifier provides a description of a pair of functions $f_0$ and $f_1$ to Peggy the quantum prover, while saving the trapdoor to $f_0$ and $f_1$;
Peggy prepares, measures, and reports the results of a register in a quantum state to provide a $y$ such that $y=f_0(x_0)=f_1(x_1)$, keeping a superposition of $\vert b\rangle\vert x_b\rangle$;
Vicky asks Peggy to measure the superposition in either the computational basis to provide a bit $b$ and an $x_b$ such that $f_b(x_b)=y$, or in the Hadamard basis to provide a string $d$ orthogonal to $x_0\oplus x_1$; and
Based on Vicky's possession of the trapdoor, Vicky can validate results (she uses the trapdoor to deduce both $x_0$ and $x_1$ from $y$ and Peggy's response above).  


Thus Peggy proves that she was able to execute a function in quantum superposition (or she has broken the security of the TCF).

The authors instantiate their TCFs with learning-with-errors (LWE), which is a leading candidate for post-quantum security.  That is, the functions they require Peggy to prepare and evaluate in superposition are associated with LWE.

My limited understanding is that the author's LWE scheme is out of reach of current and near-term noisy, intermediate-scale quantum computers.  The authors appear somewhat optimistic that about 50 bits of security may correspond to a machine with about 2000 or so qubits, or perhaps even 200-500 noisy qubits if they could optimize their LWE scheme.  

Nonetheless the scheme is interesting and I think close to the spirit of the question.  For example, in this scheme Peggy does not actually find the claw by herself but only provides a proof that she possessed $x_0$ and $x_1$ in superposition.