To prepare grits, bring the milk and broth to a boil in a medium saucepan. Stir in grits and jalapeño. Cover, reduce heat, and simmer 5 minutes or until thick. Stir in the cheese; cook until cheese melts. Spread grits into a 9-inch square baking pan coated with cooking spray; cover and refrigerate for 8 hours or until set.
To prepare peppers, cut the bell peppers in half lengthwise; discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet, and flatten with hand. Broil 15 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 15 minutes. Peel and cut into 1-inch strips. Combine peppers, oil, vinegar, coriander, and salt; toss well.
Invert grits onto a cutting board. Cut grits into 4 (4 1/2-inch) squares. Cut each square diagonally into 2 triangles. Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add triangles; cook 4 minutes on each side or until lightly browned. Serve pepper mixture over grit cakes.