Combine olive oil and garlic in a blender; process on high speed until combined. Place mixture in a small container; set aside.
Cut halibut into 3-ounce medallions, then wrap in plastic wrap and pound very gently with a mallet. Dust fish with flour, then pat with hands to shake off excess. Season fish with salt and pepper. Sauté fish in olive oil about 45 seconds each side; set aside, but keep warm.
Add butter to the pan used to sauté the fish. Heat over medium until it foams. Add 1 teaspoon garlic puree. Add verbena; cook garlic until it starts to turn brown. Slice lemon in half. Wrap lemon in cheesecloth; squeeze lemon into garlic mixture. Add parsley. Remove verbena from the pan. Adjust seasonings by adding salt and pepper.
Drizzle sauce over fish before serving.
Makes: 4