This Low FODMAP Pan Bagnat is elegant, easy and perfect for packing for lunch at work.
For the Dressing: Place the oil, vinegar, mustard, chopped olives, anchovies, scallions and capers in a glass covered jar and shake vigorously. Taste and season with salt and pepper. Set aside. This can be made a day ahead and sit at room temp.
For the Sandwich: Place drained tuna in a bowl and drizzle a little of the dressing over it and toss to mix.
Slice baguette lengthwise but do not cut all the way through; leave it “hinged”. Stir the basil and parsley into the dressing; set aside. Spoon the chunky dressing on both cut sides of the bread. It will begin to soak in, which is what you want. Scatter tuna evenly over the bottom half, then top with sliced egg, tomato and roasted pepper. Close up the sandwich, wrap tightly in plastic wrap or foil and weigh down with a large heavy skillet (like cast iron) for at least 15 minutes. The pan bagnat is ready to eat, or keep wrapped and refrigerate up to overnight (some like then even “older” than that!)