Make the spice mixture. In a bowl, combine the salt, pepper, cayenne powder, and paprika.
In a shallow dish, whisk the buttermilk and four eggs. Add half the spice mixture and continue whisking until smooth. In a gallon freezer bag, combine flour with the remaining spice mixture.
Heat up the Oil:
Place a large skillet with the canola oil on the stove and heat on low as you dredge the tenders.
Dredge the Chicken Tenders:
Add all the chicken tenders to the buttermilk and egg mixture and use tongs to evenly coat all of them. Add about 5 of the tenders to the freezer bag with the flour and seal it. Shake the bag around to evenly coat the tenders with the flour.
Fry the Chicken Tenders:
Turn the heat up to medium-high for a few minutes. Add a tiny drop of water to see if it sizzles. If it sizzles, begin frying the chicken. Add the chicken tenders, being careful not to overcrowd the pan. Fry for 6-7 minutes or until very golden brown on the bottom. Flip and continue frying another 6-7 minutes or until completely golden brown all over. Note: the first batch will take the longest since your oil isn't super hot yet. The rest will go quickly. Adjust the heat as necessary to keep the tenders from burning.
Once the first batch is golden brown all over, transfer to a paper towel-lined plate. Continue frying the rest of the tenders in batches, adding a line of paper towels between each layer of tenders to soak up the excess grease. After each batch, sprinkle a bit of flaky sea salt on top of the finished tenders if desired. Keep warm.
Prepare the Horseradish-Honey Mustard:
In a saucepan, combine the horseradish, honey, and mustard and cook over low heat until well combined and thickened, about 5 minutes. Transfer to one or two small bowls.
To Serve:
Serve the chicken tenders with the horseradish-honey mustard. Enjoy!