Place cream cheese, peanut butter, and butter in a large bowl. Beat with an electric mixer until completely combined, about 2 minutes.
Add in the powdered sugar and brown sugar. Beat 1 minute.
Add the flour, if using. Ensure it is cooked through to prevent food poisoning. Mix completely.
Add in the vanilla extract and salt, mix, then M&Ms and chocolate chips.
Serve or refrigerate until ready to serve.
Notes
Optional: 1/2 cup flour, for texture. Flour MUST be cooked in the microwave for 2 minutes or cooked in the oven at 350F for 10 minutes, stirring once, to kill any bacteria. I recommend leaving it out.