2tablespoonsolive oil, plus more for greasing the pan
1/4heaping teaspoonfine sea salt
Preheat the oven to 375ºF and grease a large baking sheet with olive oil.
On a cutting board, remove the mushroom stems, then slice the mushroom caps into 1/4-inch thin slices.
Transfer the sliced mushrooms to the greased baking sheet, and toss them with the 2 tablespoons of olive oil and salt. Use your hands to make sure they are coated evenly, then arrange them in a single layer without overlapping the pieces.
Bake the mushrooms at 375ºF for 20 minutes, then use a fork to flip each slice over. Return to the oven for 5 to 10 more minutes, until the mushroom bacon looks darker and golden, without burning. It should feel like it's getting crispy around the edges, but it's okay if the centers are still soft. They will crisp up as they cool.
Allow the bacon to cool completely on the pan, at least 15 minutes. Then pat with a towel to remove any excess oil and serve.