Using a moist paper towel, wipe the tops of the mushrooms to remove any loose grit.
Combine the mayonnaise, Treasure Cave® Crumbled Blue Cheese, basil, lemon zest and lemon juice in a food processor and pulse until combined. Then, season with salt and pepper, to taste. Set aside.
Heat the stove-top grill pan to medium-high heat.
Drizzle the caps with olive oil and season them liberally with salt and pepper. Then, place the caps face down on the heated grill with the cup side up. Drizzle the Worcestershire sauce in each mushroom cup. Simultaneously, add the red peppers to the grill and cook them for 1–2 minutes per side. Grill the mushrooms for 3–4 minutes on each side, until they’re tender.
While the mushrooms cook, add the herb butter to the outside of all the bread slices. Note: Place the butter in the microwave for 15 seconds before spreading it on the bread to ensure it spreads evenly.
Remove the mushrooms, reduce the heat to medium, add the bread to the grill, buttered sides down, and smear the basil blue cheese sauce on the insides of the bread (the face-side-up pieces).
Build the sandwiches directly on the grill. On half of the slices of bread, place the mushrooms and peppers, followed by the bacon. Then, place the other slices on top and continue to cook until they’re golden brown on each side with nice grill marks, 3–4 minutes per side.
1 stick unsalted butter, softened
1 teaspoon green onion
1 teaspoon parsley
¼ cup Treasure Cave® Crumbled Blue Cheese
Combine all the ingredients in a food processor and pulse until well combined. Chill until ready to serve.