Preheat oven to 375°F Fahrenheit.

Wash Brussels sprouts and cut off the outside leaves / ends. Cut each sprout in half.

Place brussels sprouts in a roasting pan or on a cookie sheet. Coat evenly with olive oil and vinegar. Add salt and pepper to taste.

Roast for 20 minutes, stirring brussels sprouts occasionally.

Once 20 minutes has passed, add chopped walnuts on top of the brussels sprouts. Cook for an additional 5 minutes.

Remove from oven and sprinkle feta on top. Serve warm.