In a large bowl, combine the lemon juice, mustards, egg yolk, capers and sambal oelek. Drizzle in the oil, whisking constantly. Adjust the seasoning.
With a knife, finely chop the meat. Add to the dressing along with the herbs and shallot. Stir to combine. Season with salt and pepper. If desired, add more sambal oelek, to taste. Serve the tartare with toasted baguette slices, homemade fries and a green salad.