Cut the butter into small cubes
Leave it at room temperature for 10 to 15 minutes
Grate the butter with a box grater
Pound it lightly between two sheets of parchment paper
Microwave it on low power for 5 to 10 seconds
Flip the butter and microwave in very short bursts if needed
Place the butter in a warm bowl or near a warm stove
Put the butter in a sealed bag and submerge it in warm water for a few minutes
Roll it flat with a rolling pin between parchment paper
Beat it briefly with a mixer or fork to soften it evenly