2 cups freshly squeezed orange juice, strained (from about 4 pounds or 8 large oranges)
2 whole fennel bulbs (about 1 ½ pounds total), trimmed
2 tablespoons olive oil, plus more for drizzling
Kosher salt and freshly ground black pepper
3 cloves of garlic, peeled and thinly sliced
¾ to 1 teaspoon crushed dried hot chilies (such as Thai chilies or red chili flakes)
6 sprigs of fresh thyme
2 tablespoons unsalted butter
Place orange juice in a small pot over medium-high heat. Gently boil, reducing heat as needed, until reduce to 2/3 cup, about 15 to 20 minutes; set aside.
Rinse and dry fennel bulbs. Using a peeler, peel away any blemishes or darkgreen spots on the outside of the fennel. Cut fennel bulbs in half lengthwise through the core. Cut each half lengthwise again into 3 (1 ¼ to 1 1/2-inchthick) wedges, leaving the core attached and wedges intact. Place on a baking sheet or plate, drizzle with a olive oil to lightly coat, and sprinkle generously with salt and pepper.
Pour enough oil into a large sauté pan to coat the bottom and place over medium heat. Once the oil shimmers, add segments of fennel and brown without moving, about 5 minutes. Flip and brown the other side, about 4 to 5 minutes more.
Add garlic and cook, shaking the pan to coat in oil, until just lightly color, about 30 seconds.
Add chili flakes, orange juice reduction, and thyme and let boil for a minute. Reduce heat to medium-low and simmer until the fennel has softened and caramelized but is still slightly firm, and the juice has reduced to a thick glaze, about 8 to 10 minutes. (If the fennel is tender before the glaze is thick enough to hold a line on a wooden spoon, transfer fennel to a plate and continue to reduce glaze.)
Add the butter and swirl the pan to incorporate. Remove from heat and discard thyme. Season glaze to taste with salt and pepper. Place fennel on a plate and drizzle with glaze.