Cook potatoes in boiling water to cover in a large saucepan 15 minutes or until just tender. Drain and let cool.
Melt 1/4 cup butter in a heavy saucepan over medium-low heat; add flour, stirring until smooth. Cook, stirring constantly, 1 minute. Gradually add milk and half-and-half; cook over medium heat, stirring constantly, until thickened and bubbly. Add cheese, Italian seasoning, and pepper, stirring constantly until cheese melts. Remove from heat.
Layer half each of egg slices, bacon, and cheese sauce in a lightly greased 13" x 9" x 2" baking dish. Top with potatoes. Top with remaining egg slices, bacon, and cheese sauce.
Combine breadcrumbs and 3 tablespoons melted butter; sprinkle over casserole. Cover and chill overnight, if desired.
Remove casserole from refrigerator. Let stand at room temperature 30 minutes. Bake, uncovered, at 350° for 30 minutes or until thoroughly heated. Garnish, if desired.
Note: A mushroom slicer makes a neat and easy job of slicing hard-cooked eggs for this recipe.