An ode to the BLT, this breakfast-ready version uses canadian bacon for a meatier twist and relies on watercress for the "L" in the sandwich, which adds a fresh, almost citrus-like crunch to each bite.
Heat oil in a large cast-iron or nonstick skillet over medium-high. Add bacon in a single layer and cook, flipping once, until warmed through, 2 to 3 minutes. Transfer to a plate; cover to keep warm.
Return skillet to medium-high (add more oil if necessary). Crack eggs into skillet, season with salt and pepper, and fry until whites are set but yolks are still runny, 3 to 4 minutes.
Spread mayonnaise onto bread; divide bacon and tomatoes between slices. Season tomatoes with salt and pepper. Top with watercress, eggs, and remaining bread slices.