I love pimiento cheese, and I've put it on burgers a few times over the years. Here's my latest version—with BACON! –Rach
Preheat the oven to 375°. For the topping, in a food processor, puree all the ingredients except the pimientos. Transfer to a bowl and mix in the pimientos.
Arrange the bacon on a slotted broiler pan or a wire rack set in a foil-lined baking sheet. Bake until crisp, about 20 minutes.
In a bowl, season the beef with salt and pepper. Mix in the grated onion with juices and the Worcestershire. Form into 4 patties (thinner in the centers for even cooking). Heat a large griddle or cast-iron skillet over medium-high to high. Add the oil, one turn of the pan. Add the patties and cook, turning occasionally, for 7 to 9 minutes.
Build the burgers with the bun bottoms, pickles, chopped onion, the patties, pimiento cheese topping, bacon, lettuce, tomato, and bun tops.