Place 4 quarts of water in a large kettle, add a bit of canola oil.
Heat the water to boiling for pasta while you prepare the sauce.Melt 1/8 cup of the butter. Add sage leaves and fry until they are crisp.
Remove and place on clean paper towel.Melt the rest of the butter.
Add sliced mushrooms.
Sprinkle with salt and pepper.
When mushrooms are slightly toasty around the edges add the sliced garlic.
Stir mixture and cook just until garlic is fragrant.
Remove and put in a bowl.Throw your pasta into the kettle of boiling water.Mix enough water with the flour to form a smooth paste. Set aside.Add about 1/2 cup water to hot pan and use a wooden spatula or spoon to scrape mushroom bits from bottom of the pan.
Heat the water to boiling. Gradually add flour paste and stir until you have a smooth sauce.
Add the mushroom mixture to reheat.Reduce heat to simmer.Drain pasta. Place pasta on plates.
Spoon up the mushroom sauce. Scatter fried sage on top.