• Preheat the oven to 300F. Prepare cookie sheet by lining with parchment paper. Slice the rolls, 12 slices from each roll.
  
• Place the bollillo slices in single layer, close together, but not overlapping.
  
• Butter them lightly, then sprinkle a little Parmesan on each, followed by freshly crushed black pepper and paprika.
  
• Place cookie sheet on the center rack. Bake for 20 min total,, checking periodically. Each oven is a little different, so baking times may vary a bit. Do a first-check after 10 min. and check again after another 5 min. Note that if the bread is 2-3 days old, it will crisp faster - so may need to adjust accordingly!
  
• Allow to cool completely (inside the oven is fine) before placing in an airtight container or plastic bag. (See notes)

Stove-top procedure if you do not have an oven

• Butter the slices lightly then place them on a large preheated griddle, buttered side down, in a single layer. Toast them for a 4-5 min on medium heat, checking frequently to ensure that they don/t burn.
• When they look slightly golden brown and crisp, transfer them to a plate, browned side up. Place the next batch of slices on the griddle to brown.
• Meanwhile, sprinkle a little Parmesan and paprika on the toasted slices - on the buttered and browned side.
• When all the slices have been browned on one side, transfer the slices back to the griddle, cheese side up- single layer again. Cover the griddle or frying pan, to trap the heat, which will make the cheese melt a little, and the paprika will spread through the butter to give the toast a reddish golden hue.
• Remove the cover after 3-4 min and continue to toast until fully crisp. . Allow to cool completely before placing in an airtight container or plastic bag. (See notes)