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1
Rinse porcini mushrooms.
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2
Place in medium bowl.
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3
Add 4 cups hot water, cover, and let stand until softened, about 20 minutes.
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4
Drain, reserving soaking liquid.
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5
Chop porcini.
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6
Heat 2 tablespoons oil in each of 2 heavy large pots over medium heat.
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7
Divide onions between pots; saute until tender, about 10 minutes.
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8
Divide sausage between pots.
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9
Increase heat to high and cook until no longer pink, breaking up into small pieces with back of fork, about 12 minutes.
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10
Divide button mushrooms and chopped rosemary between pots and stir until mushrooms begin to soften, about 8 minutes.
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11
Divide porcini, wine, and bay leaves between pots and boil until almost all liquid evaporates, stirring frequently, about 6 minutes.
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12
Divide porcini soaking liquid between pots, leaving sediment behind.
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13
Divide beef broth between pots.
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14
Boil until sauce is syrupy, stirring occasionally, about 20 minutes.
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15
Divide half and half between pots; boil until thickened slightly, stirring occasionally, about 5 minutes.
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16
(Sauce can be made 1 day ahead.
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17
Cool slightly, then cover and chill.
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18
Rewarm before continuing.)
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19
Brush four 3 1/2-quart glass or porcelain baking dishes with oil.
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20
Cook pasta in 2 large pots of boiling salted water until just tender but still firm to bite, stirring occasionally.
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21
Drain.
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22
Divide pasta between sauce in pots; stir to coat.
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23
Mix 3 cups cheese into each pot.
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24
Season pasta with salt and pepper.
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25
Divide among prepared baking dishes.
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26
(Can be prepared 1 day ahead.
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27
Cover and refrigerate.
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28
Bring to room temperature before continuing.)
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29
Preheat oven to 375F.
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30
Cover dishes with foil.
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31
Bake pasta just until hot but not bubbling, about 25 minutes.
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32
Sprinkle with additional cheese.
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33
Garnish with rosemary sprigs and serve with additional cheese.
