Let the rye bread or French bread slices dry uncovered overnight or lightly toast them and let dry at room temperature for 30 minutes.
Coarsely grate the roasted beets; set aside.
Tear or cut French bread into 1-inch pieces (about 6 to 7 cups); place in a large bowl with the milk and raisins; let bread pieces soak for 30 minutes.
In a separate bowl, whisk the eggs, sugar, vanilla extract, lemon zest, salt, and pepper together. Pour egg mixture over the soaking bread/milk mixture.
Crush the bread mixture with your hands until well mixed. Let the mixture sit for 1 hour, stirring occasionally.
Preheat oven to 350 degrees F. Position oven rack in center of oven.
When ready to bake, generously butter a 13x9-inch baking pan or dish. Coat the bottom and the sides of the pan well with the butter.
Spread 1/2 of the bread pudding mixture into prepared pan or dish. Cover the top evenly with the grated beets. Then spread the remaining bread pudding mixture over the beets.
Bake, uncovered, approximately 40 to 50 minutes, until set in the center, and the edges start getting a bit brown and pull away from the edge of the pan.
Remove from oven and let cool on a wire rack for 10 minutes before cutting into squares.
To serve, cut into squares and put into individual serving dishes.
Serve with dollops of sour cream or pour some cream over the top. NOTE: Best fresh and eaten the day it is made.
Makes 10 to 12 servings.
* Learn how easy it is to Oven-Roasted Fresh Beets.
Roasted Beet Bread Pudding Recipe: https://whatscookingamerica.net/desserts/beetbreadpudding/beetbreadpudding.htm