It's funny. You make a slider out of beef and throw some fried onions on it and you're at a sports bar. Dress it up with a bit of spice rub and swap out the meat for lamb, and you've got haute cocktail party fare. Either way, sliders are delicious.
I saw a variation on this coffee spice rub in a magazine years ago and have been using it to crank out little lamb burgers since. Beyond mini-meaty goodness, they also goes great with nearly any drink: beer, wine, Martinis, really anything. They can be mass produced fairly quickly too once the rub is made.
Caramelizing the sliders on a skillet or frying pan is an optional (but absolutely worthwhile) step as they get beautiful crunchy outsides and super juicy insides. Beware the massive amount of smoke that comes up off the skillet though (my smoke alarms always go off when making these.)
Little lamb sliders have been a mainstay of my holiday and cocktail parties and I hope you enjoy them! —InSearchOfLostThyme
Spice Rub for the Lamb
instant espresso powder
ancho chile powder, though any smoky chile will do
Heat the oven to 450. Meanwhile, mix all the ingredients in the first part to make the spice rub. Make sure it's all mixed well (the brown sugar always likes to clump.)
Take the ground lamb and form it into 2.5 oz patties. These should be about golf ball sized and should look like they're just a little bit too big for the brioches.
In a bowl or on some parchment paper, lay out a few of the lamb patties and start applying the spice rub. Be generous with the rub and make sure it coats the slider but don't grind it in.
(Optional) Heat up a large skillet or frying pan over medium high heat. Give the sliders a quick sear on both sides and make sure the sides of the slider get a little searing on the edge of the pan. This should be a minute at most so the rub caramelizes but doesn't burn.
Toss the sliders on a roasting pan (I usually do 6-10 at a crack) and put into the oven for ~4-5 minutes.
Take the sliders out of the oven, give them a flip, and put them back in for another 2 minutes for medium doneness. Remove from oven.
Slice the brioches in half and give each brioche top a thin coat of mayo, followed by a sprinkle of pepper. The mayo and the juices from the slider do something magical together.
(Optional) Toast the brioches slightly for 45 seconds in the oven prior to applying the mayo.