Vegetarian Sandwich Recipe

Prepare pickled onions

Thinly slice the 1/4 medium red onion into rings or half-moons. In a small bowl or jar, combine 3 tbs white or apple cider vinegar, 3 tbs warm water, 1 tsp sugar and 1/4 tsp salt. Stir until sugar and salt dissolve. Add the sliced onions, press them down so they're submerged, and let sit for at least 10 minutes (can sit up to 1 hour for more flavor).

Toast bread

Lightly brush both sides of 4 bread slices with the 2 tbs butter or olive oil. Heat a skillet over medium heat and toast each slice 1–2 minutes per side until golden and slightly crisp. Alternatively, use a toaster or oven broiler. Remove and keep warm.

In a small bowl, combine 3 tbs mayonnaise, 1 tsp Dijon mustard, 1 tsp fresh lemon juice, 1 tsp salt and 1/2 tsp black pepper. Stir until smooth and taste; adjust seasoning if needed. This will be spread on the toasted bread slices.

Prepare vegetables

Wash and dry the lettuce leaves. Slice the tomato into 4 thin slices. Slice the cucumber into 6–8 thin rounds. Halve and pit the avocado, scoop out 1/2 avocado and thinly slice or mash lightly with a fork and season with a pinch of salt and pepper. Remove the red onion from the brine with tongs and let excess liquid drip off. Prepare 2 slices of cheese.

Assemble sandwiches

Spread about half of the mayonnaise mixture on two toasted bread slices (these will be the bottom slices). Layer on 2 lettuce leaves, then place tomato slices (divide evenly), add cucumber rounds, then the avocado (sliced or lightly mashed), followed by the pickled red onions, and then the cheese slice. Drizzle a little olive oil (about 1 tsp split) over the veggies and season lightly with salt and pepper. Spread the remaining mayonnaise mixture on the remaining two toasted bread slices and place them on top, press gently.

Serve

Cut each sandwich in half diagonally if desired. Serve immediately while bread is still warm and crisp. Leftover pickled onions can be refrigerated up to 5 days.