In a large mixing bowl, combine the softened cream cheese, brown sugar, powdered sugar, vanilla extract, cinnamon, and salt. Using a hand mixer or stand mixer, beat on medium speed for 2-3 minutes, stopping to scrape down the sides, until the mixture is completely smooth, light, and fluffy.

Reduce mixer speed to low. Add the Greek yogurt (or sour cream) and mix just until fully incorporated and smooth, about 30 seconds.

Remove the bowl from the mixer. Add about 3/4 of the toffee bits. Using a spatula, gently fold them into the cream cheese mixture until evenly distributed.

Transfer the dip to a serving bowl. Sprinkle the remaining toffee bits over the top as garnish.

Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld and the dip to firm up slightly.

While the dip chills, prepare your apple slices. To prevent browning, you can toss them in a small bowl of cold water with a squeeze of lemon juice, then pat dry before serving.

Serve the chilled dip cold with apple slices, pretzels, graham crackers, or your favorite dippers.