import re
steps = [
'mix butter , flour , 1 / 3 c',
'sugar and 1-1 / 4 t',
'vanilla'
]
steps_new = [re.sub(r'(\d+\s*/\s*\d+)|\s+', lambda x: x.group(1) or "", x) for x in steps]
print(steps_new)
aW1wb3J0IHJlCnN0ZXBzID0gWwonbWl4IGJ1dHRlciAsIGZsb3VyICwgMSAvIDMgYycsCidzdWdhciBhbmQgMS0xIC8gNCB0JywKJ3ZhbmlsbGEnCl0Kc3RlcHNfbmV3ID0gW3JlLnN1YihyJyhcZCtccyovXHMqXGQrKXxccysnLCBsYW1iZGEgeDogeC5ncm91cCgxKSBvciAiIiwgeCkgZm9yIHggaW4gc3RlcHNdCnByaW50KHN0ZXBzX25ldykK