Heat a heavy, ovenproof skillet. Melt the butter, then stir in half a cup of the honey, vanilla, brown sugar, thyme sprigs, and a pinch of salt. Bring to a gentle simmer, and cook, stirring constantly, for 2 minutes. 

Arrange the pears cut side down in the skillet. Simmer for 2-3 minutes, then flip the pears over and transfer the skillet to the middle rack of the oven. Bake 12-15 minutes, until the pears are tender and the sauce is deeply golden and caramelized.

While the pears are in the oven, beat the whipping cream with an electric mixer until stiff. Fold in the remaining 2 tablspoons of honey, a pinch of salt, and cinnamon. Beat one more minute, and then fold in the Greek yogurt.

Serve the pears piping hot, drizzled with some of the honey-brown sugar sauce and topped with the yogurt cream.