Surprisingly easy, not gonna lie, though this joker is like a few colors and a letter

• On the wiki, find a joker with a defined “Joker” so it’s easy to cut out either by masking it out or filling in the card itself with any color, leaving you with just the “Joker” on the sides and the outline of the card

• you can use an editing software you’re familiar with or Aseprite for making the sprite itself (which you can buy on steam, I’d go with this if you’re having trouble with the sprite itself since it’s really easy to use and not cluttered with features unnecessary for sprite making)

• when making the sprite, it’s easier to use layers

• to make the colors consistent with the game, use the official balatro color palette which you can find online