You need a 4mm crochet hook and dk cotton.
Crochet 10 ch stitches, ss with first ch stitch.
You have one loop. One ch stitch for height. Then 18 dc.
Then 9 dc. One ch for height. Turn work.
4 dc stitches. In middle stitch 3 dc stitches, followed by 4 dc stitches. One ch stitch for height.
1rst row: 5 dc stitches, in middle stitch 3 dc stitches. Followed by 5 dc stitches. One ch stitch for height. Turn work.
2nd row: 6 dc, three dc in middle stitch, 6 dc, one ch stitch for height, turn work.
once you have completed the 13th row, cast off last stitch.
Your first square is ready.
You can play with colours: you can have stripey squares or plain one.
You crochet the four squares together.
This is the outcome:
You can find the original pattern in German here: https://www.handmadekultur.de/projekte/topflappen-aus-4-quadraten_30431
You can make smaller squares. My pot holders are 23 cm wide. But 19 cm would be ideal.
My granny used to have pot holders on hooks next to her oven. She used them when she had to fetch a hot cake tin, a casserole or a pyrex glass out of the oven.
Nowadays, Germans hang these oven gloves up as kitchen decoration.