A loaf of Westphalian style pumpernickel bread (ingredients: rye, water).
I don't like the North American version of "pumpernickel" (with molasses and coffee and sugar and what-all else to make it look like bread, but taste like cake). I really enjoy the stuff that can be legally labeled as Pumpernickel in Germany! I used to make my own home-style version occasionally, but it needs to bake for 24 hours and I don't really trust my cranky old oven to behave itself with an overnight bake anymore. Now, if I had a stone pizza oven outside where I could bake it properly
If it needs to be a "sweet" choice, then I'd have to go with the Pflaumenkuchen (German plum cake) made by a bakery in a small town just north of us. Their version is on a yeast base, more tart than sweet, and we make a trip there at least once per year just for this cake.
Sir Terry Pratchett: "Science is not about building a body of known 'facts'. It is a method for asking awkward questions and subjecting them to a reality-check, thus avoiding the human tendency to believe whatever makes us feel good."