How to Make It
Preheat the oven to 350°. In a medium saucepan, heat 1 tablespoon of olive oil. Add the pear slices and cook over high heat, stirring occasionally, until golden, about 4 minutes. Add the brown sugar, vinegar, mustard seeds and ginger and simmer over moderately low heat until slightly reduced and jamlike, about 30 minutes. Let the chutney cool.
Meanwhile, in a large skillet, heat 1 tablespoon of the olive oil. Add the bacon and cook over moderate heat until crisp, about 5 minutes. Transfer the bacon to a work surface and coarsely chop. Add the onion to the skillet and cook over moderate heat until softened, about 6 minutes. Add the sauerkraut and cook, stirring, until slightly dry, about 3 minutes. Add the pear puree, caraway seeds and chopped bacon and cook for 1 minute longer. Transfer the relish to a bowl and let cool.
Wipe out the skillet and heat the remaining 1 tablespoon of olive oil until shimmering. Season the pork with salt and pepper, add it to the skillet and cook over moderately high heat, turning occasionally, until browned all over, about 6 minutes. Transfer the pork to a roasting pan and roast until an instant-read thermometer inserted in the thickest part registers 140°, about 10 minutes. Transfer the pork to a cutting board and let cool, then cut into 1/4-inch-thick slices.
Spread the relish on the bottom halves of the baguettes and cover with the pork; season with salt and pepper. Top with the chutney and spinach; close the baguettes. Cut into 8 sandwiches and serve.
To make pear puree, drain one 15-ounce can of pears, then puree the pears until smooth.