FILLING: Melt butter and brown sugar. Stir until thoroughly combined. Bring to a boil over high heat and cook to soft ball stage (240° on candy thermometer). Remove from heat. Combine pecans and cream and add to caramel mixture. Pour over baked crust and smooth it out. Chill thoroughly.
GLAZE: Melt chocolate and butter in microwave or in simmering water. Spread evenly over filling. Chill until set and cut into bars.