Croque Monsieur with Slow-Fermented Dough and Béchamel

Method

1. In a large bowl, combine 2 cups bread flour, 1 teaspoon salt, and 1 packet (2 1/4 teaspoons) active dry yeast.
2. Mix in 3/4 cup water and knead for 10 minutes until smooth and elastic. Let the dough rise in a warm place for 2 hours until doubled in size.
3. Preheat oven to 400°F (200°C).
4. While the dough rises, prepare béchamel sauce by melting 2 tablespoons butter in a saucepan, add 2 tablespoons flour, and cook for 1 minute.
5. Gradually add 2 cups milk while stirring continuously. Cook until thickened, about 5 minutes.
6. Season with 1 clove minced garlic, 1/2 teaspoon salt, 1/4 teaspoon pepper, and a pinch of nutmeg.
7. Slice the fermented bread and spread a layer of béchamel on one half.
8. Layer sliced ham and Gruyère on top.
9. Top with the other half of the bread and press gently.
10. Bake for 10-12 minutes until golden and bubbly.