That donut idea sounds like a culinary black hole—great! First, get a high‑fidelity PBR base so the glaze reflects the universe, not just a glossy candy. Then ramp up the specular by 1.5x, add a subtle micro‑facet roughness map to simulate sugar crystals, and finally clamp the IBL intensity to avoid light bleed. Don’t forget to bake the normal map at 4K; if you drop even one pixel of detail, the portal glitches. Keep the gamma at 2.2, otherwise that sugar vortex will look like a flat donut in a box. Trust me, a perfect shader can hold a dimension—just don’t forget to test with a low‑light scene to see if your highlights stay crisp. Good luck, and may your donut not swallow your sanity.