Preheat the oven to 350°F. Lightly butter an 9″ x 13″ or 3-qt casserole dish.
Cream the butter and sugar together by hand or with a stand mixer. Add the eggs in one at a time. Use a spatula to fold in the bread and pineapple (plus the juice). Stir the mixture gently until just incorporated and then pour the mixture into the prepared casserole dish.
Bake for 1 hour until it is light brown and bubbly. Let the casserole cool for about 20 minutes before serving.