Cook the bacon in a large skillet over medium heat, stirring occasionally, until browned and crisp (4 to 5 minutes). Transfer the bacon with a slotted spoon to several layers of paper towels to drain, leaving the bacon fat in the skillet.
Add garlic and raisins to the skillet and cook over medium heat, stirring until the garlic is barely golden, about 1 minute. Stir in vinegar, oil, salt and pepper, then remove from heat.
Meanwhile, steam the broccoli in the steamer basket of a large pot with a lid just until tender (7 to 9 minutes). Transfer the broccoli to a bowl.
Bring dressing to a simmer, then cook, stirring, for one minute. Pour the hot dressing over the broccoli and sprinkle with bacon. Toss to combine.