Ingredients
 coriander seed 1/2 tsp
 fennel seed 1/2 tsp
  cumin seed1 tbsp
 mayonnaise3 tbsp
 garlic2 cloves
pressed
 lemon1 1/2 tsp
freshly squeezed
 ground lamb1 lb
 avocado oil2 tbsp
 butter2 tbsp
softened
 slider buns4 whole
preferrably brioche, challah, or any other small soft buns, split horizontally
 shallot1 whole
thinly sliced
 spring mix lettuce
 tomato4 slices

cookware

small mixing bowl
spice grinder or equivalent
mixing bowl
cast iron skillet
1
In a spice or coffee grinder, grind the seeds to a fine powder. Start with the coriander and fennel seeds. Transfer them into a separate bowl for use with the ground lamb.
2
Grind the cumin seeds to a fine powder. Reserve 1/2 teaspoon of the cumin powder for the aioli and combine the rest with the coriander and fennel powder for the lamb.
3
Make the aioli by combining the 1/2 teaspoon of cumin with the pressed garlic, mayo and lemon. Adjust lemon to taste. Mix well, and reserve. This can be made in advance.
4
In a bowl, combine the lamb and mixed ground spices and knead lightly until well combined. Divide the lamb mixture into 4 equal portions. Shape and flatten each portion into patties slightly wider than the buns and set aside. (The patties will rise and shrink when cooked, so they will fit perfectly in the buns if you shape them slightly larger when raw.) The patties can also be made in advance. Cover and store in the fridge for up to 8 hours before cooking.
5
Preheat the cast iron skillet over medium-high heat. Add the oil and warm it until it ripples. Add the lamb patties and cook on the first side for about 3 minutes, or until browned. Using a spatula, turn and cook for about 3-4 minutes, or until browned on the second side but still lightly pink in the center. Transfer to a paper towel-lined plate to drain excess oil.
6
Butter the buns with softened butter. Lightly toast the the buns by heating them cut side down in the drippings in the cast iron skillet over medium-high heat. Dab off excess drippings before toasting if needed.
7
Spread the cut sides of each bun with the cumin aioli. Divide the shallot slices evenly among the bun bottoms. Add a layer of lettuce, then top with a burger, a tomato slice, and a bun.