We develop an operator
Cq(Ψ𝒬) on the space 𝒮k(𝒩,Ψ) of Hilbert cuspforms as an alternative to the Hecke
operator Tq for primes q dividing 𝒩. For f ∈𝒮k(𝒩,Ψ) a newform, we have
f∣Cq(Ψ𝒬) = f∣Tq. We are able to decompose the space 𝒮k(𝒩,Ψ) into a
direct sum of common eigenspaces of {Tp,Cq(Ψ𝒬) : p ∤ 𝒩,q∣𝒩}, each of
dimension one. Each common eigenspace is spanned by an element with the
property that its eigenvalue with respect to Tp (resp. Cq(Ψ𝒬)) is its p-th (resp
q-th) Fourier coefficient. We finish by deriving bounds for the eigenvalues of
Cq(Ψ𝒬).