Arrange a rack at center position and preheat over to 400 degrees.
Smash heads of garlic with your hand to break them into cloves. Lightly smash cloves with the back of a large knife so that the paper coating is loosened. Then remove and discard coating. Place cloves in a 2-cup or similar size oven-proof ramekin and pour olive oil over cloves to cover completley, adding more oil if needed. Cover tightly with a double thickness of aluminum foil and bake until cloves are very tender when pierced with a sharp knife and light golden, about 30 minutes. Watch carefully toward the end of the cooking time.
Remove cloves with a slotted spoon to a mixing bowl and add 1/2 cup of the oil in which they were roasted and the butter. Smash the garlic with a fork to combine well with butter and oil. Garlic mixutre can be prepared 1 day ahead. Cool, cover and refrigerate. Bring to room temperature 30 minutes before using.
Bring a large pot of water to a boil and add linguine and 1 tablespoon salt. Cook paste until just tender, 4 - 5 minutes or according to package directions, then drain in a colander and return to the pot. Add garlic mixture and creme fraiche; toss well to combine. Stir in half of the Parmesan, !/2 teaspoon red pepper flakes and 1/2 cup of the parsley. Mix well. Taste and season with salt and with a pinch or two more of red pepper flakes if desired.
Mound pasta in 4 shallow bowl and sprinkle each serving with some remaining Parmesan and parsley.
Go to full version of