Hearty Truffles were a rare ingredient in Breath of the Wild but nowhere near as rare as they are in The Legend of Zelda: Tears of the Kingdom. It appears the gloom that has infested Hyrule has chased all hearty ingredients into the skies (where players can find Hearty Radishes) or the caves, where 
Hearty Truffles and 
Big Hearty TrufflesTears of the Kingdom.
How to Find Hearty Truffles in Tears of the Kingdom
When looking for Hearty Truffles, the best thing to do is set the Purah Pad Sensor+ to 'Hearty Truffle' and traverse caves and wells around Hyrule. In order to do this, however, the player needs an initial picture of a Hearty Truffle, which can be found in the following locations in Tears of the Kingdom:
Sturnida Secret Hot Springs Cave
- Coordinates: -4041, 2673, 0025
Up to four Hearty Truffles are located in the Sturnida Secret Hot Springs Cave, which is a huge glowing cave full of different types of mushrooms. From the Hot Springs Cave entrance, follow the trail of breakable boulders to a blue breakable boulder, and the mushroom cave can be found behind that.
Highland Stable Well
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Coordinates: 0536, -3430, 0047
The Highland Stable Well is home to two Hearty Truffles that are well-guarded by plenty of enemies. Be sure to activate Utsushok Shrine nearby for an easy fast travel point.
Satori Mountain Foothill Cave
- Coordinates: -2198, -0811, 0117
At the southeast of Satori Mountain in the Central Hyrule area is Satori Mountain Cave, where players can go to grab three Hearty Truffles. Players can access this point by paragliding west from Hyrule Field Skyview Tower or, if already activated, fast traveling to Usazum Shrine and heading north-west.
How to Find Big Hearty Truffles in Tears of the Kingdom
Big Hearty Truffles are the larger counterpart to Hearty Truffles that restore more hearts, bonus hearts, and sell for more money. They are significantly rarer than Hearty Truffles and are usually only found one at a time. Big Hearty Truffles can be found in Highland Stable Well and Upland Zorua Cave as listed above, as well as in the following locations:
Gerudo Canyon Mine
- Coordinates: -2676, -2403, 0079
The Gerudo Canyon Mine is a large, sprawling cave in the Gerudo area. Players can easily find the entrance located halfway up a wall southwest of Gerudo Canyon Skyview Tower.
Oakle's Navel Cave
- Coordinates: 2504, -2101, 0009
Accessible by paragliding north from Rabella Wetlands Skyview Tower is Oakle's Navel Cave, next to a small lake by the same name. Deep within the cave is Tokiy Shrine; the Big Hearty Truffle is right next to it.
Robred Dropoff Cave
- Coordinates: 2494, - 1483, 0014
Robred Dropoff Cave is a multilevel cave marked by a Blupee at the entrance. The area is quite isolated from shrines and towers but can be accessed by traveling southeast of Kakariko Village. The Big Hearty Truffle is on the lowest level of the cave.
Upland Zorua Byroad Cave
- Coordinates: 2865, 0332, 0230
Just north of Ralis Pond in the Zora Region is the southmost entrance of the Upland Zorua Byroad cave, where players can find one Big Hearty Truffle. The entrance is handily marked by a Blupee that will run in the direction of the Big Hearty Truffle.
Uses for Hearty Truffles in Tears of the Kingdom
Hearty Truffles can be eaten uncooked to restore two hearts in a pinch and sold for twenty Rupees, but the best use for Hearty Truffles is to cook them into a meal that can restore a lot of bonus hearts. The same goes for Big Hearty Truffles, which sell for twenty-five Rupees and can be eaten raw for three hearts.
Best Recipes that Use Hearty Truffles
- Hearty Mushroom Skewer - Two or more Hearty Truffles or Big Hearty Truffles. Each Hearty Truffle is equal to one additional bonus heart, and each Big Hearty Truffle is equal to four.
- Hearty Steamed Mushrooms - To maximize bonus hearts, cook Hearty Radish and/or Big Hearty Radish with Hearty Truffles and/or Big Hearty Truffles for a ton of bonus hearts.
Additionally, adding one Hearty Truffle to a meal made up of food that has no base effect will ensure the dish restores Link's full health, plus at least one bonus heart.
Dying Armor
Hearty Truffles can also be used to dye armor black at the Kochi Dye Shop, but given their rarity, they should be saved for cooking. Big Hearty Truffles can be used to dye armor white, but they're even rarer, so they should also be saved.
The Legend of Zelda: Tears of the Kingdom is available for the Nintendo Switch.