Roast the garlic. Preheat the oven to 400°F (200°C). Cut the top off a garlic bulb, drizzle lightly with olive oil, wrap in foil, and roast for 40–50 minutes until soft. Cool completely and mash 4–6 cloves.
Mix the butter. Place the softened butter in a bowl. Add the roasted garlic, chopped parsley, rosemary or thyme, and optional salt. Mix until evenly combined.
Prepare the mold. Use a clean, food-safe mold, such as a suitable paper cup. Make an opening in the base and position the approved wick according to its manufacturer's instructions. Secure it upright.
Fill the mold. Spoon the garlic herb butter around the wick, pressing gently to remove large air pockets. Smooth the top and check that the wick remains centered.
Chill until firm. Refrigerate for at least 2 hours, or until the butter is firm throughout.
Remove the mold. Carefully peel or cut away the mold without breaking the butter. Place the candle upright on a heat-safe, rimmed serving dish.
Serve with bread. Arrange sliced baguette or sourdough around the candle. If lighting it, follow the wick manufacturer's instructions and supervise the flame continuously. Extinguish it before it becomes unsafe. Alternatively, serve the butter unlit as a flavored compound butter.