Season both sides of each beef roulade with salt and pepper. Brush one side with mustard. Cover each with 2 slices of ham. Place a pickle at one end and roll up tightly. Secure with toothpicks or roulade skewers at the ends and middle.
Heat oil in a large pan over medium-high heat. Brown the roulades for 3-4 minutes on each side. Transfer to a casserole dish.
In the same pan, sauté the finely diced onions over medium heat for 2-3 minutes until softened. Increase heat to high. Add 1 tablespoon mustard and 1 tablespoon tomato paste. Cook and stir constantly for 1-2 minutes until caramelized. Slowly pour in the red wine while stirring to create a smooth sauce. Bring to a boil.
Add the meat broth, a splash of pickle juice, and the 3 bay leaves. Mix the cornstarch with a little water until smooth. Stir the cornstarch mixture into the sauce and bring to a boil.
Pour the sauce over the roulades in the casserole. Cover and cook for 1 hour at 200°C (400°F) in the oven, or covered on the stovetop over low heat.
Season to taste with salt and pepper before serving.