In a skillet, heat olive oil over medium heat. Add garlic and sauté until fragrant.

Add spinach and cook until wilted. Remove from heat and let cool.

In a bowl, combine the cooled spinach mixture with cream cheese, feta, salt, and pepper.

Lay the flank steak flat on a clean surface. Spread the filling evenly over the steak.

Starting from one end, roll the steak tightly into a log. Use plastic wrap to help shape it.

Wrap the rolled steak tightly in plastic wrap and refrigerate for at least 30 minutes.

Preheat the grill to medium-high heat. Remove the steak from the refrigerator and unwrap.

Slice the rolled steak into 1-inch thick pinwheels.

Grill the pinwheels for about 5-7 minutes on each side or until desired doneness.

Let rest for a few minutes before serving. Garnish with chopped parsley if desired.