Sift Bowl 1: Add the dry ingredients (flour, sugar, cocoa powder, and baking soda) to a fine mesh sieve or sifter and sift together.
Add Wet Ingredients: Add oil, water, vinegar, vanilla, and salt to the bowl and beat with a hand mixer until all ingredients are just combined.
Mix Bowl 2: Add cream cheese and sugar to a medium-sized bowl and cream with a hand mixer. Add egg and salt and mix until it's all combined and creamy.
Prep Toppings: Add chocolate chips and walnuts to small bowls and set aside.
Preheat Oven: Prehead oven to 350 degrees F and line a mini muffin tins with liners.
Fill Muffin Tin: Use a tablespoon measuring spoon to add 1 tablespoon of the chocolate mixture from bowl 1 to the mini muffin liners. This will fill the liners a little over 3/4 the way full. Then use a teaspoon measuring spoon to top the chocolate with 1 teaspoon of the sweet cream cheese mixture from bowl 2. Sprinkle with some chopped walnuts and then finish with 4 chocolate chips. Repeat until all of the chocolate and cream cheese filling is used.
Bake: Add trays to the oven and bake for 15 minutes. Remove from oven and let cool for 5 minutes in the trays and then remove from trays and let cool on cooling racks.
Enjoy!