Heat a large skillet over medium heat and add the butter and olive oil. Sprinkle the peaches with the salt and place them cut-side down in the skillet. Cook until the peaches begin to turn golden, 2 to 3 minutes. Flip the peaches and cook on the other side for 2 to 3 minutes. Sprinkle the cut sides with the brown sugar. Flip again and cook for another 5 minutes. Pour in the bourbon to deglaze the pan and toss and flip the peaches a few times.
Whisk together the mascarpone, heavy cream, honey and vanilla until smooth.
Divide the peaches among 4 plates and top each with a few dollops of the mascarpone cream. Add another drizzle of honey if you'd like more sweetness. Sprinkle with fresh mint and serve.