In a small saucepan, heat honey over medium-low heat until it begins to thin out, approximately 3 minutes. Add vinegar and salt, and bring to a simmer. Cook until mixture reduces by half, approximately 15 minutes. Transfer mixture to a heatproof bowl, and let cool.
Notes
Gastrique can be made up to a week in advance. Store in an airtight container, and refrigerate until needed.
Recipe by TeaTime Magazine at https://teatimemagazine.com/brussels-sprout-pancetta-canapes-with-apple-cider-gastrique-recipe/