Cheddar & Onion Recipe

Prepare the onions

Place the thinly sliced red onion in a small bowl. Add 1 tablespoon of water and 1/8 teaspoon kosher salt; toss to combine. Let sit for 5 minutes to soften and mellow the bite. After 5 minutes, drain any excess liquid and pat the slices lightly with paper towel if very wet. Toss with 1 teaspoon olive oil and 1 teaspoon chopped fresh parsley (if using), and season with 1/4 teaspoon black pepper. Set aside.

Make the spread

In a small ramekin stir together 1 teaspoon mayonnaise and 1/2 teaspoon Dijon mustard until smooth. This will help bind the cheese and add tang.

Assemble the sandwich

Spread 1 tablespoon of the softened butter evenly on the outer side of each bread slice (these sides will be grilled). On the inner side of one slice, spread the mayonnaise-mustard mixture. Pile 1 1/4 cups grated sharp cheddar evenly onto the same slice. Distribute the prepared sliced onions over the cheese so they are in an even layer. If you like a touch more herb, sprinkle an additional 1/2 teaspoon parsley over the onions. Top with the second bread slice, inner side facing the filling.

Grill the sandwich

Heat a skillet or griddle over medium-low to medium heat. Once warm, place the sandwich buttered-side down on the skillet. Press gently with a spatula or a second pan to compress slightly. Grill for 3–4 minutes until the bottom is golden brown and the cheese begins to melt. Flip the sandwich carefully and grill the other side 2–4 minutes until golden and the cheese is fully melted. If the bread is browning before the cheese melts, reduce the heat to low and cover the pan with a lid for 1–2 minutes to help the cheese melt through.

Finish and serve

Transfer the sandwich to a cutting board and let rest 1 minute. Slice in half diagonally. Serve immediately. Estimated calories for this sandwich are about 780 kcal.