Rinse the beef tongue under cold water
Trim off any excess fat or debris
Place the tongue in a large pot
Add enough water to fully cover the tongue
Add salt, onion, garlic, bay leaves, and peppercorns if desired
Bring to a boil
Reduce to a simmer
Cook until tender, about 2.5 to 4 hours
Check tenderness with a fork
Remove the tongue from the pot
Let it cool slightly
Peel off the outer skin while still warm
Slice or chop the tongue as desired
Serve as is or use in tacos, sandwiches, stews, or other dishes