Cut the top off of each apple and core. Use a paring knife to cut one to two rings around the inside of the apple. Make vertical cuts around the outside of the apple about ¼” apart, slicing through to the first inside ring. Stop your vertical cuts about ¼” from the bottom so the apple stays intact. Make vertical cuts around the interior ring of the apple, again stopping about ¼” from the bottom. Repeat for each apple.
Place apples in a lightly greased baking dish. Place 2-3 walnuts inside the core of each apple.
Make the crumb topping by mixing flour, brown sugar, baking powder, cinnammon, salt, oats, and butter together. Mix until crumbled texture appears. Top each apple with a generous amount of crumb topping.
Bake apples for 35-40 minutes, or until apples begin to "bloom" and are tender. While the apples are baking, make your dipping sauces.
Peanut Butter Dipping Sauce
Combine all ingredients in a small saucepan. Heat on low. Stir frequently until thoroughly combined and smooth.
Sweet Orange Dipping Sauce
Add cornstarch to cold orange juice and stir until dissolved. Add salt and sugar and stir until combined. Heat in a saucepan on medium-low heat. Stir frequently until sauce thickens.
Caramel Dipping Sauce
Mix brown sugar, half and half, butter, and salt in a small saucepan over medium-low heat. Whisk gently and cook for 5-7 minutes. Add vanilla and cook additional minute. Remove from heat and let cool.
Notes
*If you want a sweeter peanut butter dipping sauce, you can add sugar or powdered sugar to taste.