Heat a cast-iron skillet over medium-high heat. Add bacon and cook until crisp on both sides, 7 to 10 minutes. Remove from pan, chop and set aside.
Reduce heat to medium-low, add the leek to the pan and saute until tender and slightly caramelized, about 10 minutes. In the last few minutes of cooking, toss in the tomatoes and cook until they just begin to blister and soften. Remove and set aside.
Use hot pan to toast bread.
To assemble, spread 3 to 4 tablespoons of goat cheese on each piece of toast. Top with leek tomato mixture and bacon pieces, and garnish with parsley.