Preheat your oven to 350°.
Beat eggs in small mixer bowl. Gradually add sugar and vanilla; beat well. Blend in melted butter.
Combine dry ingredients; gradually add to egg mixture until well blended. Stir in nuts (if using).
Spread in greased 8-inch square pan. Bake at 350° for 30-35 minutes or until brownie begins to pull away from edges of pan. Frost if desired.