1. superlative form of buttery; containing the most butter or having the strongest butter flavor
2. superlative form of buttery; having the smoothest, most slippery, or most slick texture or appearance

Examples

• These are the butteriest croissants I've ever tasted.
• The butteriest part of the popcorn is always the most popular.
• Her voice had the butteriest, smoothest tone in the choir.
• The butteriest sauce coated the pasta perfectly.
• That's the butteriest leather I've felt on a jacket.
• The butteriest biscuits came straight from the oven.