1

Heat oil in a large nonstick skillet over medium-low heat. Add the fennel and radicchio and cook, stirring occasionally, until very soft, about 30 minutes. Meanwhile, spray a broiler rack with nonstick spray; preheat the broiler or grill.

2

Reserve 8–12 blackberries; combine the remainder in a small saucepan with the broth and thyme; bring to a boil, then cook until the berries are easily mashed, about 2 minutes. Transfer to a fine-mesh sieve set over a bowl; press the berries with the back of a spoon, taking care to scrape the residue from the outside of the sieve into the bowl. Return the puree to the saucepan.

3

In a small bowl, dissolve the cornstarch in the orange juice. Add to the puree. Cook over medium heat, stirring constantly, until the mixture thickens, bubbles, and turns translucent, about 2 minutes.

4

Broil or grill the steaks 5 inches from the heat until an instant-read thermometer inserted into the center of each steak registers 160°F for medium, 145°F for medium-rare, about 1 1/2 minutes on each side for medium-rare. Slice into thin strips.