Line a baking sheet with parchment paper and set aside. The parchment paper should be smooth and even, with no wrinkles or creases.

In a medium-sized bowl, mix together the Greek yogurt, honey, and vanilla extract until smooth and creamy. The mixture should be pale yellow in color and have a thick, creamy texture.

Melt the dark chocolate chips in a double boiler or in the microwave in 30-second increments, stirring between each interval until smooth. The chocolate should be melted and smooth, with a glossy appearance.

Pour the melted chocolate onto the prepared baking sheet and spread into a thin layer. The chocolate should be evenly spread and have a smooth, glossy surface.

Spoon the yogurt mixture on top of the chocolate layer, leaving a 1-inch border around the edges. The yogurt mixture should be dolloped on top of the chocolate in small, rounded spoonfuls.

Top with chopped nuts and any optional fruits, nuts, or spices. The toppings should be evenly distributed and add a pop of color and texture to the bark.

Refrigerate for at least 30 minutes or until set. The bark should be firm to the touch and have a smooth, even surface.

Break into pieces and serve. The bark should break cleanly and have a smooth, creamy texture.