1. Preheat oven to 400°F. Line a rimmed baking sheet with parchment.

Hasselback Apples

1. In a small bowl, melt the butter and sugar together in the microwave. Alternatively, melt them in a small saucepan over medium heat. Mix until the sugar is melted. Stir in the cinnamon. Set aside.
2. Peel the apples, then cut in half from stem to bottom. Using a spoon or melon baller, remove the core, leaving as much of the apple as possible.
3. Place the apple half cut side down on a cutting board and cut 1/8-inch slices being careful you do not cut all the way through the bottom. You want the slices to be like the pages of a bound book held together by a sturdy spine.
4. Place the apples on the prepared baking sheet. Brush with melted cinnamon butter. Cover the pan with aluminum foil and bake for 20 minutes.

Streusel Topping

1. In a small bowl, mix the brown sugar, flour, and cinnamon to combine. Toss in the butter cubes and using a fork, cut the butter into the flour until crumbly.
2. Remove the apples from the oven. Increase oven to 425°F and remove the foil from the apples. Using the fork, top each apple with a good tablespoon of the streusel, using the tines to press the topping between the slices. Repeat until all the topping is used up. Don’t worry if some topping falls into the pan. You can gather this up later for extra crunch.
3. Return apples, uncovered, to the oven, and bake another 10 to 15 minutes. The apples should be tender but not falling apart. The streusel should be crisp.
4. Let cool a few minutes. Top with vanilla ice cream, if desired. Scoop up and break apart any fallen streusel to sprinkle on top.
5. Serves 4.