8 medium shallots (about 7 ounces total), peeled
1 teaspoon kosher salt
2 cups canola oil
1 tablespoon freshly ground black pepper
1 tablespoon large, flaky sea salt, such as Maldon
Line a small baking sheet with 8 paper towels; set aside.
Slice the shallots very thinly on a mandoline to the thickness of a dime.
Place oil in a medium straight-sided sauté pan or sautoir. The oil should come up about ¾-inch.
Add shallots to the oil and set the pot over medium-high heat. Stir the shallots continuously every 2 minutes with a fork to keep the rings from sticking together. Do not let oil get hotter than 375°F. Try and stay around 365°F.
Using a slotted spoon or spider, transfer shallots to a rack set over a baking sheet. Then transfer shallots to baking sheet lined with paper towels. Remove one paper towel at a time, letting each layer of paper towel absorb excess oil.
Let oil in the pot cool completely. Strain oil through a fine meshed sieve into a medium bowl. Reserve this shallot-infused oil for the beef marinade.
Once completely cooled, transfer fried shallots to a small food processor or spice grinder. Pulse, in batches if needed, until coarsely ground. Use should have about ½ cup chopped shallots. Mix with the freshly ground black pepper and flaky sea salt. Hold in an air-tight container for up to 2 months.