This thumbprint cookie uses honey as the only sweetener and tender ground almonds to replace much of the butter found in similar cookies. Just a touch of butter mixed with honey in the filling gives it a rich flavor without too much saturated fat.
Process whole almonds in a food processor or blender until finely ground (you will have about 1 1/4 cups ground). Transfer to a large bowl and add whole-wheat flour, all-purpose flour, baking powder and salt; stir until just combined. Beat 2¿3 cup honey, oil and 3 tablespoons butter in a mixing bowl with an electric mixer on medium speed until well combined. Add egg and vanilla and beat until blended. Add the wet ingredients to the dry ingredients; stir to combine. Refrigerate the dough for 1 hour.
Preheat oven to 350 degrees F . Coat 2 baking sheets with cooking spray or line with parchment paper or nonstick baking mats.
Roll tablespoons of dough into 1-inch balls and place on the prepared baking sheets about 2 inches apart. Press the tip of your index finger in the center of each cookie to make an indentation. Bake the cookies, in batches, until set and barely golden on the bottom, 13 to 15 minutes. Transfer to a wire rack; let cool for 30 minutes.
Combine the remaining 1/4 cup honey and 1 tablespoon butter in a small bowl until creamy. Use about 1/4 teaspoon to fill each cookie and top with 2 sliced almonds, if desired.
Tip: To toast whole almonds, spread on a baking sheet and bake at 350 degrees F , stirring once, until fragrant, 7 to 9 minutes. To toast sliced almonds, cook in a small dry skillet over medium-low heat, stirring constantly, until fragrant and lightly browned, 2 to 4 minutes.
Ingredient note: Look for whole-wheat pastry flour in the natural-foods section of large supermarkets and natural-foods stores.
MAKE AHEAD TIP: Store in a single layer in an airtight container for up to 2 days.