Preheat oven to 400 degrees F. Coat a 12-cup muffin pan with cooking spray. Set out strawberries to thaw slightly.
Process almonds, 2 tablespoons brown sugar, 1 teaspoon orange zest and 1/4 teaspoon salt in a food processor until finely ground. Transfer to a small bowl. This will top your muffins!
Whisk all-purpose flour, whole-wheat flour, baking powder, baking soda and the remaining 1/4 teaspoon salt in a large bowl. Whisk 1/3 cup of the brown sugar, 2 teaspoons orange zest and oil in a medium bowl with buttermilk, orange juice, egg and vanilla extract until well combined. Make a well in the center of the dry ingredients and pour in the wet ingredients; stir until just combined. Chop the strawberries, add to the bowl, and stir just to combine. Divide the batter among the prepared muffin cups. Sprinkle with the almond topping, gently pressing into the batter.
Bake the muffins until golden brown and a wooden toothpick inserted in the center comes out clean, 18 to 20 minutes. Let cool in the pan for 10 minutes, then transfer to a wire rack to cool for at least 5 minutes before serving.