Heat a large skillet over medium-high heat. Add the bacon in a single layer and sprinkle lightly with half of the brown sugar. Cook for 4–5 minutes, then flip and sprinkle with the remaining brown sugar. Cook until crispy and caramelized. If the bacon is too large for the pan, cut it in half and cook in batches. Transfer to a paper towel–lined plate.

In a large bowl, use a hand mixer or stand mixer to beat together the cream cheese, mayonnaise, salt, and pepper until smooth and creamy.

Slice the bagels in half and toast until golden.

Spread the mayo cream cheese mixture evenly over the bottom halves of the bagels, then layer with bacon, lettuce, and tomato. Top with the remaining bagel halves.

Assemble, serve immediately, and enjoy!