Thanks to Huangism for pointing me to Adding text before list, where I found my solution:
ol {
list-style-type: none;
counter-reset: elementcounter;
padding-left: 0;
}
li:before {
content: "Step " counter(elementcounter) ". ";
counter-increment: elementcounter;
font-weight: bold;
}
<ol>
<li>Place bag in freezer, etc...</li>
<li>Preheat oven</li>
</ol>
I had to tweak the padding-left because list-style-type: none;
got rid of the automatic numbering, but still left the space it would've taken up.
Result:
Step 1. Place bag in freezer, etc...
Step 2. Preheat oven