Two ideas--posted together because they are related.
1. Nut trees--give off a basic nut (almonds maybe?) that can be converted to other kinds using something akin to a fruit machine. If we want to avoid making yet one more converter tool, then perhaps the fruit machine can be updated to become a fruit & nut machine. Have two actions on it--convert fruits, convert nuts.
2. Food processor--used to process different foods into stuff, especially the nuts into nut butters (add some oil and salt to these). Other recipes: process beans into hummus (with garlic and lemon juice), apples into apple butter (and other fruit butters), tomatoes/onions into salsa, onions/spices into chutneys.