Place almonds in zipper-lock bag and, using rolling pin, pound until no pieces larger than 1/2 inch remain. Combine pounded almonds, honey, mustard, vinegar, and shallot in medium bowl. Whisking constantly, drizzle in olive oil until emulsion forms. Add water and tarragon and whisk to combine, then season with salt and pepper. Serve.

Makes about 1/2 cup