Place mushroom caps on a baking sheet and drizzle with olive oil and salt, to taste. Place mushrooms in oven for 20 minutes, flipping halfway through.
Cook bacon in a large skillet over medium-high heat, flipping every 1-2 minutes, until crispy. Once crisp, remove bacon from pan and place on a plate lined with paper towels to drain excess grease. Set pan with bacon grease aside.
In a small bowl, mix together all the seasonings with a fork, then set aside.
In a large bowl, mix ground pork and maple syrup. Add in seasoning mixture and thoroughly combine with the pork.
Using your hands, separate pork mix into 8 balls then, lightly, press them in between your hands to create 3-4 inch patties.
Heat the pan with bacon grease. Once the pan is hot, cook patties in the grease, about 4 minutes on each side. Remove from pan, then set aside.
To serve, place 1 mushroom cap on a plate and top with pork sausage, avocado, and bacon.
Optional: Top with second mushroom cap to make them into a breakfast burger!