The key is getting it to stick together. Divide up the mixture and place it into each of the mushroom caps. Fill each cap, pressing down to make certain the mixture fills all the nooks and crannies. Bake at 350-degrees for 30 minutes. You want to make certain everything is hot clear through and the cheese melted.
Many recipes use egg instead of olive oil as it enhances the binding of the materials.
This is a fairly flexible recipe. You just have to adjust the crumbs and oil mix to get everything to hold together for stuffing.