2/3 c. unsalted butter, softened
1/2 c. light brown sugar
1 tsp. vanilla
1 c. finely chopped pecans
1 1/2 c. flour

Heat oven to 325 degrees. Generously butter a 9 inch round cake pan. Beat butter and brown sugar until fluffy. Beat in vanilla. Combine pecans and flour. Add to butter and brown sugar mixture in 4 portions. Pat mixture into pan and pierce on top. Bake until slightly brown and puffy, about 30 minutes. Cut while warm.