Prep the vegetables: Wash and thoroughly dry all produce. Cut broccoli and cauliflower into small, even florets. Slice cucumbers into coins.
Cut the yellow bell pepper into flat panels and use a small star-shaped cutter, or carefully trim a star with a knife.
Make the yogurt dill dip: In a bowl, combine Greek yogurt, dill, chives, Dijon, lemon juice, lemon zest, garlic, salt, pepper, and olive oil if using. Stir until smooth. Taste and adjust seasoning with more salt, pepper, or lemon.
Chill the dip: Cover and refrigerate at least 20 minutes.
This helps the flavors meld and slightly thickens the dip.
Choose your platter: Use a large cutting board, slate board, or rimmed baking sheet. Place a small bowl near the bottom third for the dip, or keep the dip on the side.
Create the tree outline: Arrange broccoli florets in a wide triangle, with the widest row at the base. Build up in layers, making each row slightly narrower as you go, to form a tree shape.
Fill and fluff: Pack the broccoli florets close together so the “tree” looks full.
Tuck cauliflower along edges or in small clusters to look like snow.
Add ornaments: Nestle cherry tomatoes around the tree as ornaments. Add radish slices and cucumber coins to bring in more color and texture.
Top with a star: Place the yellow bell pepper star at the top of the tree. Add small herb sprigs like dill or parsley as “garland.”
Make the trunk: Line up a few pieces of broccoli stem, cucumber slices, or even pretzel rods at the base to form a trunk.
Finish and serve: Set the chilled dip in the bowl and drizzle a few drops of olive oil on top if you like.
Sprinkle with a little extra dill or black pepper. Serve immediately, or refrigerate for up to 2 hours before serving.