Begin by slicing one lemon thinly and setting it aside for layering. Zest and juice a second lemon, ensuring you capture every drop of tangy goodness. Then, take your sweet onion and slice it into thin rings.

In a medium measuring cup, combine olive oil, white wine vinegar, lemon juice and zest, Creole seasoning, salt, minced garlic, granulated sugar, and optional mustard seeds. Whisk everything together until emulsified.

Grab two wide-mouth canning jars and start layering your ingredients. Begin with a layer of sweet onion rings, followed by slices of lemon, then add the shrimp, and finish with a bay leaf.

Carefully divide the prepared marinade between the jars, ensuring even coating. Seal tightly and gently turn them over several times.

Place the jars in the refrigerator, allowing them to chill overnight. Turn the jars 2-3 times to ensure thorough marination.

After marinating, remove the jars from the refrigerator, and serve the shrimp with visible layers. Serve on their own or with toasted baguette slices.