Preheat oven to 450°F and prepare a rimmed baking sheet by lining it with parchment.
Remove stems from mushrooms and with a damp paper towel, gently wipe them clean. Place onto the prepared baking sheet.
In a medium skillet over medium heat, melt the Kerrygold Pure Irish Butter. Add the onion and garlic, and sautée until soft, about 1 -2 minutes. Add the sausage, sage, thyme, and Cajun seasoning and cook until well browned.
In a medium bowl, put the cream cheese and grated Kerrygold Skellig cheese. Add the sausage and with a rubber spatula, blend well.
Distribute the sausage filling among the mushrooms, and sprinkle the Kerrygold Savory Shredded Cheddar on top of each one.
Bake for 8 -10 minutes. Remove from the baking sheet and place on a lined paper towel to drain.