Preheat the oven to 400F. Place the gluten-free flour blend, baking powder, xanthan gum (if using), and salt in a large mixing bowl. Whisk to combine. Add the Greek yogurt.
Stir until combined and a dough forms. Place the scraggly dough onto a floured piece of parchment paper, the size of a large baking sheet, about 10x15-inches large. Pat into a ball or disk.
With a (gluten-free) floured rolling pin, roll the dough out into a large rectangle that is almost as big as the baking sheet. Transfer the parchment paper with the dough onto the baking sheet.
Brush the dough with olive oil. Poke a few holes in the dough with a fork to prevent it from bubbling up in the oven.
Bake at 400F for 23-27 minutes, until golden brown. Place on a wire rack to cool completely.
Once the crust has cooled, make the dill cream cheese spread. Combine the cream cheese, Greek yogurt, garlic powder, onion powder and fresh dill. Stir to combine until the dill is thoroughly incorporated.
Spread the cream cheese mixture on the cooled crust, leaving a 1-inch border on all sides.
Slice the slice into 20 squares. It’s easier to slice the crust now than after the vegetables are on top.
Divide the sliced red bell pepper, cucumber, broccoli, radishes, carrots and green onions over the cream cheese mixture. Serve immediately or refrigerate until ready to serve.