In a small saucepan, warm 3 tablespoons of honey over low heat. Once warm but not boiling, add 1 tablespoon dried lavender buds and remove from heat. Cover and let steep for 10 minutes.
Strain the honey through a fine-mesh sieve, pressing gently to extract all the lavender-infused honey.
Preheat your oven to 350°F (175°C). Peel, core, and slice the apples into ¼-inch thick pieces.
In a large bowl, toss the apple slices with the lavender-infused honey, lemon juice, vanilla extract, cinnamon, and nutmeg.
Sprinkle cornstarch over the apple mixture and toss until evenly coated.
In a separate bowl, combine the rolled oats, flour, brown sugar, and salt.
Using your fingertips or a pastry cutter, work the cold butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized butter pieces remaining.
Transfer the apple mixture to a 9x9 inch baking dish, spreading it evenly.
Sprinkle the crisp topping over the apples, making sure to create an even layer. If using, scatter chopped pecans and the additional teaspoon of lavender buds over the top.
Bake for 45-50 minutes until the filling is bubbling around the edges and the topping is golden brown. If the topping browns too quickly, tent with aluminum foil for the remainder of the baking time.
Allow the crisp to rest for 15-20 minutes after baking before serving.