For a hands-off approach (with no grease to wipe up), bake bacon on a foil-lined sheet pan in a 350°F oven. In a large bowl, whisk the flour, sugar, baking powder, baking soda and salt.

Cook until soft, then blend to a smooth puree. Cook the bacon until crisp and golden. Place on kitchen paper and wilt the scallions in the fat. Cut 8 slices of the bread and spread mayonnaise and ...