3 slices of bacon, cut crosswise into 1/2-inch strips
1 pound shelled and deveined large shrimp
Kosher salt and freshly ground pepper
One 15-ounce can cannellini beans, drained and rinsed
1/4 cup plus 1 tablespoon extra-virgin olive oil
1 small shallot, minced
1 tablespoon Dijon mustard
1/4 cup red wine vinegar
Spread the spinach on a large platter. In a large skillet, cook the bacon over moderate heat until crisp, about 4 minutes. Drain off all but 2 tablespoons of the bacon fat. Season the shrimp with salt and pepper and cook it with the bacon over moderately high heat until just white throughout, about 4 minutes. Add the beans, season with salt and pepper and toss until heated through, about 1 minute. Scrape the shrimp and beans onto the bed of spinach.
In the same skillet, heat 1 tablespoon of the olive oil. Add the shallot and cook over moderately low heat until softened, about 1 minute. Add the mustard to the skillet and whisk in the red wine vinegar, then whisk in the remaining 1/4 cup of olive oil. Season the dressing with salt and pepper, pour it over the salad and serve.