Step 1: Chill your mixing bowl and whisk attachments in the freezer for at least 15 minutes. This helps the cream whip up faster and more stable.
Step 2: In the chilled bowl, combine the very cold heavy cream, granulated sugar, and vanilla extract.
Step 3: Using an electric mixer, start on low speed and gradually increase to medium-high. Whip the cream until firm peaks form. Be careful not to over-whip, as it can become grainy. The cream should be thick enough to hold its shape well.
Step 4: Lay out two slices of crustless shokupan on a clean surface. Spread a generous, even layer of the whipped cream on one side of each bread slice, going all the way to the edges.
Step 5: Arrange the whole, dried strawberries on one of the cream-covered bread slices. Strategically place them so that when the sandwich is cut diagonally, you'll see a beautiful cross-section of strawberries (e.g., one in the center, and others forming a square or diamond around it).
Step 6: Gently place the second cream-covered bread slice on top of the strawberries, cream-side down. Press down very lightly to ensure the bread adheres to the cream and strawberries without squishing them.
Step 7: Carefully wrap the assembled Japanese Strawberry Sando tightly in plastic wrap. This is crucial for helping the sandwich set and making it easier to slice cleanly.
Step 8: Refrigerate the wrapped Japanese Strawberry Sando for at least 30 minutes, or up to 2 hours. This chilling time allows the cream to firm up and the flavors to meld.
Step 9: Once chilled, unwrap the sandwich. Using a very sharp, long serrated knife, slice the sandwich diagonally from corner to corner to reveal the stunning strawberry pattern. For clean cuts, wipe your knife clean between each slice if making multiple.
Step 10: Serve your beautiful Japanese Strawberry Sando immediately and enjoy its simple elegance.