Pick your goal: roast/crisp (use tallow or lard), flavor-forward baking (butter + oil), or “just fat” baking (shortening).
Measure by the listed ratio (use weight where possible for consistent browning).
Adjust cooking: rendered fats brown faster—start checking 2–4 minutes earlier for high-heat roasting.
If the substitute is less savory (olive oil or shortening), increase seasoning or add aromatics (garlic/thyme/rosemary) to replace lost depth.
For crispy textures, dry the surface well (pat protein/vegetables dry) before adding the fat.