In a large bowl, combine the streusel ingredients with a spoon until moistened and crumbly. Set aside. Meanwhile, in the bowl of a stand mixer, cream the butter and granulated sugar together until fluffy, about 1 minute. Beat in the eggs, one at a time, followed by the vanilla and vanilla bean caviar. Add in the Greek yogurt/sour cream and mix well, followed by 2 cups of the flour, the baking powder, and baking soda until a smooth batter comes together. Lastly, beat in the fig preserves. In a small bowl, combine the chopped figs with the 2 Tbsp flour until coated; fold the flour-coated fig pieces into the cake batter gently.