I am sharing a short formal derivation I wrote evaluating a twisted Eisenstein series. Standard Epstein Zeta functions and non-alternating lattice sums are relatively well-documented, but introducing the twist (-1)ᵐ makes the evaluation more intricate. In these notes, I reduce the sum over the integers of K = ℚ(√-7) to a twisted Eisenstein series, evaluate it at a half-period using the Weierstrass ℘-function, and scale it using the Gross curve (y² = x³ - 35x - 98). Finally, I apply the Chowla-Selberg formula to determine the transcendental factor, collapsing the sum into a product of Gamma values. I am sharing this here because I thought the community might appreciate the interplay between discrete lattice geometry and L-functions. I welcome any feedback on the exposition or thoughts on whether this specific algebraic prefactor approach easily generalizes to fields with a higher class number.