Preheat the oven to 350 degrees F.
In a large skillet heat 1/4 cup of the olive oil over medium-high heat and fry the eggplant slices until golden brown on both sides, adding more oil as needed. Remove the eggplant from the skillet and blot lightly on paper towels.
Spread the mustard and blue cheese over bread. Arrange the eggplant slices, Layer the tomatoes and roasted peppers on top and sprinkle with cheese. Cover with the other half of the bread, pressing firmly to join.
Cut the sandwich in 2 pieces. Brush each side of the bread with olive oil. Heat a large skillet over medium-high heat and grill both sides until golden and crispy.