"L'il Woody's executive chef Cory Alfano said he was inspired by the fresh flavors of summer when he created this burger served as a weekly special at the beloved Seattle restaurant: Imagine a nice summer Pacific Northwest day and wanting to grill some burgers with friends. Super easy, just go down to your local farmers market and pick up some fresh ingredients from local purveyors to make an amazingly light but meaty late-afternoon grilled burger. Heirloom tomatoes, arugula, red onions, local cheese, and grass-fed beef make this 'Farmers Market Burger' a sure thing."
Combine sea salt, porcini mushrooms, thyme, garlic powder, 1 teaspoon black pepper, and red pepper flakes in a food processor; blend until thoroughly mixed. Pour seasoning mixture into a bowl.
Combine egg yolks, lemon juice, garlic, and dill in the food processor; blend, pouring in canola oil and olive oil in a steady stream until aioli is thick and smooth.
Combine sliced onions, red wine vinegar, sugar, salt, and pepper in an airtight container. Let marinate, at least 15 minutes.
Preheat an outdoor grill for medium heat and lightly oil the grate.
Spread buns on grill and toast until golden, 30 seconds to 1 minute. Transfer to a serving platter. Spread some aioli over each half.
Shape ground beef into 6 large patties. Sprinkle seasoning mixture generously over both sides.
Increase grill heat to high. Grill patties until browned and an instant-read thermometer inserted into the center reads 160 degrees F (71 degrees C), about 4 minutes per side.
Place 1 cooked patty on the bottom of each toasted bun. Top each with 3 tablespoons goat cheese, 2 tomato slices, 1 heaping tablespoon pickled red onions, and 1/2 cup arugula. Cover with top half of the bun.
You can make the seasoning mix in a spice or coffee grinder instead of a food processor if preferred. Leftover seasoning mix can be stored in an airtight container for up to 6 months. Use on burgers or other grilled meats.
Extra aioli will keep in an airtight container in the refrigerator for up to 4 days; extra pickled red onions will last up to 6 months.
Brush brioche buns with melted butter before assembling burgers.
Nutrition data for this recipe includes the full amount of seasoning mix, aioli, and pickled red onions. The actual amount consumed will vary.