Preheat oven to 350°F.
Arrange bread slices on cooling racks set over baking sheets. Bake until lightly golden, around 10 minutes.
Heat a medium-size, deep skillet over medium heat. Add butter and melt. Add flour and gently cook, whisking flour and butter together, until smooth and flour has had a chance to cook, about 3 minutes.
Slowly add milk while continuing to whisk. Gently bring milk to a bubble while stirring frequently. Allow the milk to thicken a bit, then stir in provolone cheese until smooth.
Heat EVOO in large skillet over medium-high heat. Sauté the onion and pepper for 5-7 minutes until softened; season with salt and pepper.