Clean the squid tube, pull the skin off and cut it up open.
In a pan, heat the olive oil to stir-fry the squid for 2.5 minutes on each side seasoning with salt and pepper. Remove from heat and cut into thin strips.
In another pan, heat some olive oil, sauté the cut squid, pour in the lemon juice and add the basil pesto. Remove from heat, stir well and finish with butter.