Baconnaise!

Attempt one to make Syris approved, paleo friendly mayonnaise :)

Here we have a room temperature egg yolk, half a tablespoon of mustard, and a cruet full (1/2-3/4 cup) of warm bacon drippings (yum).
The actual emulsifying process is not as difficult as it seems, just beat the yolk/mustard constantly (I used the beater pictured, but I've heard food processors/blenders work too) while very slowly adding your fat of choice. I like the cruet because it keeps the pouring steady but slow. I kept my bowl on a damp towel to keep it from sliding all over the place.

Eventually, it ends up looking something like this. It seems counter-intuitive, but the more oil that is added, the thicker the mayonnaise.
At this point, I added a splash of apple cidar vinegar. This lightens the mayonnaise and adds flavor. Salt and pepper can be added to taste.

Finally, I added a teaspoon of whey and left the mayonnaise to sit, covered, on the counter for a few hours. This lacto-ferments the mayonnaise, making it slightly thicker and last longer in the refrigerator.
We'll call this experience a semi-success, as the mayonnaise did turn out and worked great in my broiled tilapia recipe. However, I didn't love the flavor or thickness (darn saturated fats) in my deviled eggs. I think next time I might try half bacon drippings with another, less saturated fat (maybe light olive oil?).