Here’s a simple mayonnaise recipe by gram:

Ingredients:

• 1 egg yolk (about 18 grams)
• 1 teaspoon Dijon mustard (about 5 grams)
• 1 tablespoon white wine vinegar (about 15 grams)
• 200 ml neutral-flavored oil (such as sunflower or vegetable oil)
• Salt to taste

Instructions:

1. In a bowl, whisk together the egg yolk, Dijon mustard, and white wine vinegar until well combined.
2. Slowly add the oil in a thin stream while continuously whisking to emulsify the mixture. This should take about 5-7 minutes.
3. Continue whisking until the mayonnaise reaches a thick and creamy consistency.
4. Season with salt to taste and whisk to combine.
5. Transfer the mayonnaise to a jar or container, and refrigerate for at least 30 minutes before using.

Note: Make sure all ingredients are at room temperature for better emulsification. Adjust salt and vinegar according to your taste preferences.