How to Make It
Preheat oven to 375°F. Using a paring knife, remove core from tomatoes, creating a 2-inch cavity in each and being careful not to cut through skin. Sprinkle tomato cavities with 1⁄2 teaspoon of the salt and 1⁄4 teaspoon of the pepper. Place tomatoes on a parchment paper-lined rimmed baking sheet.
Bring chicken broth to a boil in a small saucepan; stir in couscous. Cover and remove from heat. Let stand 5 minutes; fluff with a fork.
Meanwhile, cook bacon in a large skillet over medium until crispy on both sides, about 4 to 5 minutes per side. Transfer bacon to a plate lined with paper towels, reserving 1 tablespoon drippings in skillet and remaining drippings in a small heatproof bowl. When bacon is cool enough to handle, roughly chop to measure about 1⁄2 cup. Reserve 2 tablespoons chopped bacon for garnish.
Cook spinach in reserved 1 tablespoon bacon drippings in skillet over medium, stirring often, until wilted, about 1 minute. Stir together spinach, couscous, feta, basil, and remaining chopped bacon, 1 teaspoon salt, and 1⁄4 teaspoon pepper in a large bowl.
Brush outsides of tomatoes with reserved bacon drippings in bowl, and stuff cavities with couscous mixture. Bake tomatoes in preheated oven until tender, about 25 minutes. Sprinkle with reserved 2 tablespoons chopped bacon, and serve immediately.