The effects of rice flour substitution with hazelnut skin (HS), hazelnut flour (HF), and HS-HF blend (1:1, w/w) at percentages of 0%, 5%, 10%, 15% (w/w) on gluten-free cake batters were studied from a rheological standpoint. Replacement with 5% HS increased Power-Law consistency index (K), reduced specific gravity and resulted in the highest cake volume. Increasing levels of HS gradually increased specific gravity, water activity, and reduced tan, leading to cakes with lower volume, darker (lower L*) color, harder texture. HF addition increased tan (at >5%) and specific gravity, producing cakes with lower volume, but similar color and texture to those of control. HS-HF blend improved cake color and hardness compared to HS added alone. Strong correlations were found between G() slope and cake volume (r=0.9939 for added HS, r=-0.9408 for added HF), the exponent a and cake volume (r=0.9447 for added HS, r=-0.8668 for added HF).