It seems to be pretty random, from what I've been able to find. From this page:
Recipes may acquire random bonuses, such as being boosted from low to mid or have extra hearts. The jingle heard is altered when the results are randomly improved.
This site also says that it is random and that it will apply one of a few different effects to your dish.
On top of these buffs, when cooking you may also hear a special sound. When this happens you will receive an extra bonus at random. These are:
- Extra yellow heart
- Three extra hearts
- Buff increase by a further 5 minutes
- Buff increased by +1
- Stamina increases
However, this article also says that there is a way to guarantee this boost.
You can actually guarantee these bonuses by using particular items or cooking during a certain time.
Cooking during a Blood Moon, when the moon is red and enemies respawn, will give you a random bonus. As will using a star fragment or dragon body part in your recipe.
Thus, it's not yet known the exact chance to have this bonus happen to you, but you're able to force it to happen by cooking under certain conditions or using certain ingredients.
According to this article you should have gotten it on your first use of the amiibo. And if you did not put Epona into a stable you may not get her to summon again. It does not seem that there are any requirements for getting her to summon other than using the amiibo and it being the first time doing so, there are no indicators that using it at a specific point in the game changes how this works.
If the player has the Smash Bros. Series Link Amiibo, you can use the
Amiibo Rune to tap Link onto the NFC reader. While most other Amiibo
will summon a supply drop of items - the first time the Smash. Bros
Series Link is used, Epona will be summoned instead.
So my guess is, based off their explanation, is that you potentially summoned her and didn't notice and it may be stuck where you can't summon her again. Or you summoned her in the Plateau and you did not get to put her in a stable, thus she disappears.
However, if you wish to keep and ride Epona - you must register the
horse at a stable as soon as possible. If you summon Epona in a place
where you cannot get to a Stable, like on the Great Plateau, you will
be unable to summon Epona again, as using the Smash. Bros Series Link
Amiibo on other days will only summon standard supply drop items.
However; there is another article that mentions a fountain that may be of help to you.
The downside, of course, is that if Epona dies -- that's it. You
cannot respawn Epona by tapping the amiibo again after she dies, and
you will only be able to get her by restarting your game or by finding
the Horse God's Great Fairy Fountain.
So perhaps there is a chance you can get Epona back, based off of what that article says:
Unlocking this Great Fairy will allow you to bring any horse back to
life -- provided that it was registered, and that you have the means
to pay for it. Even legendary or rare horses can be brought back to
life at this fountain -- including Epona (provided you already
summoned her with an amiibo).
But since it doesn't seem like you registered her if she did spawn by chance, it may not work either. The only solution remaining after that, as far as I can tell, is restarting, which I can't imagine you want to do.
Best Answer
The name, effects, and image of the food or elixir you produce is not important. The sell value of your cooking is entirely dependent on only two factors:
The price is determined by the following formula:
Multiply this by:
Round the resulting number to the next ten. (101 -> 110, 87 -> 90, etc)
Here's an example:
You cook four Gourmet Meats. Each meat sells for 35 rupees. Add them together and you get 140. Multiply this by 2.4 because you use four ingredients. This gives you 336, so you need to round it up to the next ten, which is 340, the sale price.
So the most profitable meals and elixirs you can cook are simply the ones made with five of the most expensive ingredients you can find. Just make sure they actually produce something edible, because if you end up with "Dubious Food" or "Rock-Hard Food", they will sell for next to nothing.
Source: GameFAQs