Almond flour would not work the same way as wheat flour or corn starch. It is the starch that does the thickening, it is a chemical reaction, not just a suspension of particles.
I like to use egg yolk, and thicken with the protien.
Take the juice from the roast, or if there is no juice put some water in the bottom of the pan (just like you would in conventional gravy) and heat it up.
In a separate bowl beat aboutn1 egg yolk per 1-2 cups of juice. The more yolk per juice, the thicker.
Temper the yolk by adding, slowly, some of the hot juice while beating. (Temperng avoids making scrambled yolks)
When the yolk is tempered (made very warm by adding the hot liquid) put it in the original pan and heat gently. You do not need to boil it, and doing so could cause it to curdle. It should thicken, and be nice and rich.
For thickening curries/gravies you can use any of these methods:
1.fried onions turned into a paste in a blender
5.Cooked mushrooms, ground into paste.
Coconut flour also works quite well as a thickener in sauces, just make sure to mix it with a little water and add the paste first instead of dumping it straight into your sauce. (Same method as you would use adding cornstarch to avoid lumps).
I use arrowroot powder. You have to be careful not to use too much, though. It'll seem like it's not going to get thick, and then suddenly it's slime worthy of the prop-master from You Can't Do That On Television. (There I am, dating myself again.)
Why not add wine to the drippings, reduce it, then add butter to thicken it a bit?
It may not work the same way, but I made a roux with almond flour and drippings and butter, and it was absolutely fabulous.
I also did a beef stew and I usually don't sear the meat, but I had a bug and I did. I tossed the meat in a bag with almond flour and spices, then seared it in coconut oil. Damn if that wasn't some of the best beef stew ever!