Preheat oven to 300F. Butter 6 8-oz ramekins. Place ramekins in a baking pan with 3-4 inch high sides.
Remove stems from mushrooms and chop them. Thinly slice muchrooms. Fill each ramekin to the top with mushroom slices. Chop any remaining mushroom slices and reserve.
Heat half-and-half in a heavy saucepan with the garlic, chopped mushroom stems (and any reserved chopped mushrooms), paprika, cayenne and thyme. Stir in the bouillon. Let the mixture simmer for 8 minutes. Pour mixture (in batches) into a blender container and puree. Pour back into pan and remove from heat.
Whisk eggs together and pour into saucepan with mushroom mixture and whisk to combine.
Pour mixture into each ramekin and pour boiling water halfway up sides of ramekins. Put baking pan in oven and bake 35 minutes. The custards are done when a knife inserted in center comes out clean.
Sprinkle each ramekin with chopped parsley. Serve warm with garlic toast points. (Use thick white sandwich bread cut into triangles or 2-inch wide slices, brush with oil and garlic and toasted in oven.)