Method

• Generously coat a 13 x 9 inch baking dish with cooking spray. Cover the bottom of the dish with half of the bread slices. Top with laf of the tomato slices. Sprinkle evenly with cooked bacon and fresh basil. Sprinkle evenly with half (about 1 ½ cups) of the cheese. Top with remaining bread slices and tomato slices in 1 layer, overlapping edges of bread and tomatoes as needed to fit.

• Process eggs, half-and-half, tomato paste, salt, granulated garlic, mustard powder, paprika, black pepper, nutmeg, and cayenne in a blender until smooth, about 20 seconds. (Alternatively, place the mixture in a large bowl, and process with an immersion blender until smooth.) Pour egg mixture slowly and evenly over bread mixture in baking dish, letting it seep down into the layers. Cover tightly with plastic wrap. Refrigerate at least 8 hours or up to 24 hours, unwrapping the dish twice and firmly pressing down on mixture to help bread absorb liquid.

• Preheat the oven to 350 F. Unwrap baking dish: sprinkle evenly with remaining (about 1 ½ cups) cheese. Bake until the casserole is deep golden and just set (a knife inserted into the center should come out moist but not wet), 45 to 50 minutes. Cool until barely warm, about 20 minutes.

• Meanwhile, whisk together mayo, lemon juice, mustard, and sugar in a large bowl until smooth. Place in the refrigerator until ready to serve.

• Add arugula to mayo mixture; toss until lightly coated. Serve alongside or on top of pain perdu.