Preheat the oven to 350°F (175°C). Grease a 9×5-inch (23×13 cm) loaf pan. In a large bowl, combine the torn bread with the whole, evaporated, and condensed milks warmed briefly until just lukewarm; fold and press to help the bread soften, then rest 10 minutes.

Make the caramel by melting the sugar in a small saucepan over medium heat until amber. Immediately pour into the loaf pan and tilt to coat the bottom and a little up the sides.

Stir the melted butter into the soaked bread. Whisk eggs with vanilla, cinnamon, nutmeg, lime zest, and salt; fold into the bread mixture. Toss raisins with flour and fold in.

Set the loaf pan in a larger baking pan and pour in hot water to reach 1 inch (2.5 cm) up the sides. Bake about 1 hour, or until a knife inserted in the center comes out clean. Cool 30 minutes, then refrigerate at least 4 hours (or overnight).

To unmold, dip the pan briefly in warm water, loosen edges with a knife, invert onto a platter, and let the caramel flow over the pudding. Slice and serve chilled.