We will need to know the relationship between cups, pounds, and ounces.
First, let's determine how many pounds are needed to fulfill the 3 cups of mushroom requirement. We know that one pound of mushrooms equals to 5.5 cups. So, if we are in need of 3 cups, we divide these 3 cups by how many cups there are in one pound.
This gives us approximately 0.5454545454545454 lbs of mushrooms.
Next, to convert this pound measurement to ounces, we use the conversion factor 16. This is because there are 16 ounces in one pound.
We multiply the pounds of mushrooms needed (0.5454545454545454 lbs) by 16 (ounces in a pound). This gives us approximately 8.727272727272727 ounces.
However, the question asks that you round your answer to the nearest ounce. Hence, the amount of mushrooms needed is rounded off to 9 ounces.
So, you would need approximately 9 ounces of mushrooms for this recipe.