Preheat oven to 350°. Grease a 1 1/2 quart casserole.
Trim crusts from bread and cut into 1" cubes.
Cream butter and sugar together. Add eggs, one at a time, and mix until well combined. Stir in pineapple. Fold in bread cubes.
Bake in prepared casserole at 350° for 1 hour, or until brown on top.