Step 1

Preheat oven to 325°F. Butter 13 x 9 x 2-inch glass baking dish. Combine first 6 ingredients in heavy large saucepan. Whisk over medium-high heat until mixture thickens but can still be poured, about 15 minutes. Remove from heat. Whisk in butter and vanilla extract.

Step 2

Transfer pudding mixture to prepared baking dish. Bake pudding until golden brown and center no longer moves when pan is shaken, about 1 hour 30 minutes. Cool 10 minutes. Scoop pudding into bowls. Top with ice cream or frozen yogurt and serve.