In a small bowl, combine salt, sucanat, paprika & ground peppercorns.
Slice the mushrooms lengthwise about 1/8" thick.
Put mushroom slices in a medium-sized bowl & coat well with grapeseed oil. Mix in the seasoning blend. Set aside for around 15 minutes to set.
Heat a large skillet over medium-high heat & add a thin layer of grapeseed oil. When it shimmers, add mushroom strips in a single layer, cook until golden brown, then flip & brown the other side.
Transfer to a plate lined with paper towels. Blot off excess oil gently. Mushroom bacon will crisp up as it cools (around 30 seconds).
A cheaper & more bacon-y tasting (albeit less healthy) version of this recipe uses canola oil instead of grapeseed, and a pre-made pork rub as opposed to the homemade spice blend.