Heat a large skillet over medium-high heat. Add bacon once hot and cook until crispy. Remove bacon with a slotted spoon and set aside.
Add the potatoes to the same pan with the bacon grease and arrange in an even layer. Season liberally with salt and pepper and let cook for about 15 minutes only tossing once browned and crispy on each side.
Meanwhile, place the portobello caps gill side up on a baking sheet and drizzle with the olive oil. Broil on high for 10 minutes until they release their water. Remove from the oven, drain the water out of the center of the caps and set aside.
Add the jalapenos to the potatoes during the last minute and toss to combine.
Turn the heat off, add the green onions, cilantro and the crispy bacon to the skillet and toss to combine.
Spoon the hash mixture into each portobello cap and top with a poached (or fried) egg.