Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius). Place an oven rack in the center position.

Peel, core, and dice the apples into small, even pieces. Smaller pieces soften more quickly and distribute evenly through the custard.

Place the apples in a baking dish and toss them with 1 tablespoon granulated sugar and 1 teaspoon ground cinnamon until evenly coated. An 8-inch or 9-inch square baking dish works well, but any similar-sized oven-safe dish is fine.

In a large bowl, whisk together the eggs, brown sugar, and granulated sugar until smooth. Whisk well enough to dissolve the sugars and fully break up the eggs.

Add the whole milk and heavy cream. Whisk until the custard mixture is completely combined and slightly frothy around the edges.

Pour the custard evenly over the cinnamon-coated apples. Use a spoon to gently nudge the apples so they are evenly distributed if needed.

Bake for approximately 35 to 45 minutes. The custard should be set around the edges and slightly jiggly in the center. The top will be golden brown.

Remove the dish from the oven and let the dessert rest for 10 to 15 minutes before serving. This rest time helps the custard finish setting and makes serving easier.

Serve warm, spooning the soft baked apples and custard onto a plate or into shallow bowls.