Put the almond butter and butter in a medium bowl and beat with a hand mixer on medium speed until light and fluffy, about 1 minute. Top each toast with some of the butter mixture, peach or nectarine slices, 1/2 teaspoon honey and some basil. Garnish the tartines with a sprinkle of Maldon salt, if desired, and serve.
If Greek honey is unavailable, you can make your own: Warm 1/4 cup of honey in a small saucepan over low heat, then add 2 sprigs of fresh thyme. Remove from the heat and let steep for 5 minutes before using.