Lay out all 8 slices of bread on a clean surface. If you prefer a toasted version, lightly butter one side of each slice and toast them in a pan until golden. For a traditional soft sandwich, skip the butter and toasting.
Using a butter knife or small spatula, spread 1 tablespoon of peanut butter evenly over one side of 4 slices. Spread gently to avoid tearing the bread, especially if using crunchy peanut butter.
On the remaining 4 slices, spread 2 teaspoons of jelly or jam. Grape and strawberry are traditional, but raspberry or blackberry also work well. Spread to the edges for even flavour in every bite.
Place the peanut butter covered slices on top of the jelly covered ones, spread sides facing each other. Press gently to seal the layers without squashing the filling.
For a neater presentation, trim the crusts using a sharp knife. This step is optional but often preferred for serving children or for a more uniform look.
Cut each sandwich in half diagonally or into quarters, depending on preference. Arrange on a plate and serve immediately, or wrap tightly for later.
Pair with a glass of cold milk, apple slices, or crisps for a classic American lunchbox feel. If packing for later, wrap in wax paper or foil to keep the bread soft.