TOMATO Jam: Heat oil in large saucepan on medium heat. Add onions; saute 2 to 3 min. until crisp-tender. Stir in garlic and cumin seed; cook several minutes or until aromatic. Stir in tomato paste; cook until heated through, stirring frequently. Add crushed tomatoes; stir. Bring just to boil on low heat; cover. Simmer 30 min. or until thickened to jam-like consistency, stirring occasionally; cool slightly. Puree until smooth. Season with salt and pepper.
FOR each serving: Brush cut sides of 1 baguette piece with 1 Tbsp. butter; toast on flat griddle. Sear 5 prosciutto slices (3 oz.) on flat-top griddle or in nonstick pan.
SPREAD 1 Tbsp. mustard onto bottom half of baguette; top with prosciutto and 1/4 cup (1 oz.) cheese. Heat under salamander 20 sec. or until cheese is melted; top with 1/3 cup arugula and 2 Tbsp. basil. Spread 1/4 cup Tomato Jam on inside of top half of baguette; use to cover sandwich. Cut diagonally in half; secure with picks.