Using Melted Butter Instead of Olive Oil

Reviewed by the CupOrGram Editorial TeamSources: King Arthur Baking, USDA FoodData CentralMethodology
Ratio
Use 3/4 cup melted butter per 1 cup oil (adds water content)
Good — works well with minor differences

Measurement Variance Note

For 1 cup references, this ingredient can vary by about 4% across brands and measuring methods (207g-225g per cup). For the most reliable substitution result, measure by weight and test a half batch first.

What changes when you swap olive oil for melted butter

Swapping melted butter into a recipe that calls for olive oil means trading a 100% fat liquid for one that's only 80% fat — the other 20% is water and milk solids, which is why the conversion lands at 3/4 cup melted butter per cup of oil. In an olive oil cake, that switch costs the open, slightly savoury crumb and pulls the bake toward a more familiar pound-cake density, with milk solids browning the edges where the oil would have stayed pale and tender. Use European-style butter (82-84% fat) if you want to narrow the moisture gap.

  • Browning ramps up — milk solids in butter Maillard at around 150 C, so a focaccia or rosemary-olive-oil loaf will darken faster and need either a lower oven or a foil tent past 25 minutes.
  • Mouthfeel turns drier as the bake cools because butter's saturated fats solidify at fridge temperature, while olive oil stays fluid — a tea cake that was sliceable on day three goes firm overnight.
  • The peppery, grassy backnote that finishes a citrus-olive-oil cake disappears entirely; lean into it by browning the butter first and adding lemon zest to compensate for the lost aromatic complexity.

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