Step 1: Prepare the Bell Peppers

Wash all bell peppers thoroughly.

Remove stems and seeds.

Slice peppers into ¼-inch strips for even cooking and crisp texture.

Step 2: Sauté the Vegetables

Heat olive oil in a skillet over medium heat.

Add onions and cook 2–3 minutes until slightly softened.

Add bell pepper strips, salt, black pepper, and lemon juice.

Sauté 5–7 minutes, stirring occasionally, until tender-crisp.

Remove from heat and let cool slightly.

Step 3: Prepare the Bread

Mix mayonnaise and Dijon mustard.

Spread evenly on one side of each bread slice.

Step 4: Assemble the Sandwich

Place a slice of cheddar cheese on one bread slice.

Layer sautéed peppers and onions evenly.

Sprinkle fresh herbs if desired.

Top with second bread slice, mayo side down.

Step 5: Toast the Sandwich (Optional)

Grill on a skillet 2–3 minutes per side until golden brown and cheese melts.