1Mix pineapple and 1 teaspoon cinnamon in a bowl. Spread each slice of bread with 1 1/2 teaspoon cream cheese. Top 2 slices with 1/4 cup pineapple mixture apiece; reserve remaining pineapple mixture. Place remaining slices of bread atop pineapple mixture and press lightly to make 2 sandwiches.
2Whisk remaining 1/2 teaspoon cinnamon, milk, egg, sugar, and vanilla extract in a shallow bowl. Lay each sandwich in milk mixture and let bread absorb mixture for a few seconds; flip and repeat.
3Heat a nonstick skillet over medium heat, melt butter in the hot skillet, and fry sandwiches on both sides in butter until golden brown, 2 to 3 minutes per side. Top each sandwich with half the remaining pineapple mixture and drizzle 1 tablespoon hot fudge sauce over pineapple.