Step 1

In a wooden bowl, add garlic, salt, pepper and dry mustard. Using the tines of a fork mash the garlic into the salt mixture until the garlic is pureed into a paste. Add lemon juice, then slowly drizzle the oil while whisking vigorously. Set aside.

Step 2

Combine lettuce, tomato and onion. Toss with the salad dressing, then let sit for at least 15 minutes to allow the lettuce to wilt a bit.