Mix together butter, pumpkin, eggs and pumpkin spice with mixer. Add box mix. Be sure to take out the frosting packet inside first. Mix until incorporated.
Line a 8 x 3 loaf pan with parchment paper. Spoon mixture in loaf pan and bake for 40 - 45 minutes.
Remove and while cooling, mix together the frosting packet with cream cheese. Remove loaf from the pan onto a serving dish. Spread frosting on top of loaf.