In a large bowl, beat eggs and sugar until well blended.
Add in vanilla and nutmeg; stir in milk.
Add bread cubes, pecans and currants to bowl and stir gently to combine. Let stand for about 10 minutes, stirring often to saturate bread with egg mixture.
Spoon bread mixture into a lightly greased 10-in. paella pan, 8-in. square cake pan or shallow 2-qt. casserole. Drizzle with 1/4 c. butter.
Preheat oven to 350°F/180°C.
Set pan of pudding in a larger baking pan that is at least 2 in. deep, then set pans on middle rack of oven. Pour boiling water into larger pan to a depth of about 1 in.
Bake until a knife inserted in center of pudding comes out clean, about 1 hour.
Serve pudding warm. Shortly before serving, prepare Bourbon Sauce. Serve warm sauce in a small pitcher or bowl to pour over pudding to taste.
For the bourbon sauce:
Melt 1/4 c. butter or margarine in a 1- or 1.5-qt. sauce pan over medium heat.
Stir in confectioners’ sugar and bourbon. Stir frequently as you cook until sugar is dissolved. Reduce heat to low.
In a small bowl, beat 1 large egg yolk. Stir in a little of the hot butter mixture; then return egg mixture to pan and cook, stirring constantly, until sauce is thickened, about 1 - 2 minutes. Remove from heat.