In a small mixing bowl, stir together the garlic powder, paprika, salt, and black pepper. Season the turkey breast all over with the seasoning mixture. Use your fingers to gently separate the skin from the meat and rub the seasoning under the skin as well. Cover and refrigerate for at least 1 hour and up to overnight.

In a small saucepan, combine the bourbon, maple syrup, apple cider vinegar, and Dijon mustard. Bring to a boil over medium heat, then lower the heat to medium-low and simmer until reduced to about ¼ cup, about 20 minutes. Remove from heat and let cool.

Add the turkey to a roasting pan, then add the slices of butter under the skin. Drizzle the turkey with olive oil.

Roast the turkey breast for 30 minutes, then brush the turkey all over with the maple bourbon glaze. Continue to cook until the internal temperature reaches 165°F (74ºC), about an additional 15 minutes. If it needs more time, continue to cook, checking the temperature every few minutes.

Remove the turkey from the oven to a cutting board and brush once again with any remaining glaze. Cover and let rest for 10 to 15 minutes. Cut into slices and serve hot or at room temperature.