For the burgers, shape the meat into 4 evenly-sized patties about 1 inch thick. Handle lightly to keep the texture light and juicy. The burgers can be shaped and refrigerated, covered, for several hours. When ready to cook, heat one tablespoon olive oil in a large skillet or grill pan over medium-high heat until very hot or build a medium-hot fire in a barbecue. Generously season the meat on both sides with salt and pepper. Cook the burgers in the skillet, turning once or twice, 7 to 10 minutes for medium-rare. Do not press down on the patties. With a large spoon, baste the burgers several times with the fat in the pan. (You can also preheat the oven to 450 degrees and cook the burgers on top of the stove until they are brown on both sides, and then finish them in the preheated oven.) To grill the burgers, oil the grate, arrange the patties on it, and cover. Cook as above. While the burgers are searing, heat up one tablespoon olive oil in a skillet over high heat, and cook the spinach stirring occasionally. Season with salt and pepper. Sauté until the leaves are wilted but bright green about 3 minutes. Keep warm. Toast the buns in a toaster oven or on the outer perimeter of the grill rack until golden brown. For the last minute of cooking, display the blue cheese over each burger to melt lightly. Then top the cheese with the warmed up shallot jam.* Top the shallots with the spinach; then remove to a warm platter, keep warm, and let rest several minutes before serving.

To assemble the burgers, divide the butter lettuce leaves between the buns and top with the tomatoes. Add the burgers and the bacon on top of each. Cover with the bun tops. Serve immediately with remaining shallot jam.