Heat a large skillet over medium to medium-high heat with olive oil, 2 turns of the pan. Melt butter into oil and when it foams, add garlic and thinly sliced lemon and swirl pan a minute. Add zest and pepper, then swirl a minute more. Add wine or stock and simmer to reduce by half, about 2 minutes. Add shrimp to sauce and cook 3-4 minutes until pink and firm. Season with salt, add the juice of the lemon used for zest, parsley and oregano, toss, transfer to plates or shallow bowls and serve with bread for mopping.