Preheat your oven to 375°F (190°C). Lightly grease a baking dish just large enough to hold all the peach halves snugly.
Prepare the peaches.
Halve and pit the peaches. If the pits cling, run a small paring knife around them or use a spoon to ease them out. Place the peach halves cut-side up in the baking dish.
Make the honey butter.
In a small bowl, whisk together the honey, melted butter, vanilla, cinnamon, and salt until smooth and glossy.
Spoon the mixture over the peaches. Divide it evenly among the cavities, letting some drip down the sides. Sprinkle the sliced almonds over the top of each half, pressing lightly so they stick.
Bake for 20–25 minutes, until the peaches are tender and the edges look slightly caramelized.
If your peaches are very firm, add 5–10 minutes and tent with foil to prevent over-browning.
Finish and serve. Let the peaches rest for 5 minutes. Spoon any pan juices over the tops.
Drizzle with a little extra honey if you like and serve warm with ice cream, yogurt, or a dollop of whipped cream.