Make the spice blend: Combine the berbere, paprika, celery salt, white pepper, cumin, garlic powder and 1 1/2 teaspoons salt in a bowl. Brine the chicken: Stir 1 cup salt and 8 cups cold water in a large bowl until the salt dissolves. Add the chicken to the brine, cover and refrigerate 1 hour, 30 minutes. Remove the chicken from the brine and pat dry. Marinate the chicken: Whisk the buttermilk, coconut milk, minced garlic cloves and 1 tablespoon of the prepared spice blend in a large bowl. (Reserve the remaining spice blend for sprinkling.) Submerge the chicken in the marinade; cover and refrigerate overnight. Heat the oil: Remove the chicken from the refrigerator and let it almost come to room temperature, about 1 hour. Fill a large cast-iron skillet about halfway with peanut oil; add the rosemary and whole garlic cloves. Heat over medium-high heat until a deep-fry thermometer registers 360 degrees F, or until a pinch of flour added to the oil sizzles and rises to the surface.
Bread the chicken: While the oil heats, mix the all-purpose flour, semolina flour, cornstarch and white pepper on a baking sheet. Remove the chicken from the marinade with tongs, letting the excess drip off. Roll the chicken in the flour mixture to coat thoroughly, then sprinkle more of the flour mixture on top.
Fry the chicken: Shake off any excess flour from the chicken, then, using tongs, carefully lower each piece into the hot oil. Fry, turning occasionally, until just cooked through, about 7 minutes. (Reduce the heat to medium if the crust starts to brown too quickly.) Transfer to a rack and let rest, 10 minutes. Discard the garlic cloves and rosemary. Fry again: Reheat the oil until a deep-fry thermometer registers 375 degrees F to 380 degrees F. Fry the chicken again, this time in 2 batches to avoid crowding the pan, until the breading is crisp and deep golden brown, about 1 minute.
Season the chicken: Transfer the chicken to the rack to cool slightly, and sprinkle with the reserved spice blend. Keep the fried chicken warm in a 250 degrees F oven for up to 1 hour before serving, or let cool and pack for a picnic.
Courtesy of Food Network Magazine. Photograph by Christopher Testani.