In a small bowl: combine all the seasonings together.
Pat the roast dry with a paper towel. Pour and rub olive oil all over the roast. Then coat the roast with the seasoning mixture. Place the roast on a dish, cover and refrigerate for at least 12 hours or up to 24 hours (recommend for 24 hours for best result).
Remove the roast from the refrigerator and let sit at room temperature for 1 hour prior to cooking. Preheat the oven to 275°F.
Bake in the oven for 1 hour for medium-rare (internal temp.130°-135°F) (highly recommended) or 1 ½ hours for medium (internal temp. 140°-145°F). Open the door and confirm the anticipated Internal temperature using a meat thermometer.
Remove the roast from the oven and let cool (uncovered) to room temperature for 30 minutes. Transfer the roast to a dish. Cover and refrigerate for at least 4 hours or overnight (preferred).
Use a meat slicer or a very sharp knife to thinly slice the meat just prior to eating. Toast bread. Spread remoulade sauce on the bread. Add roast, tomatoes, lettuce & onions.