Preheat the oven to 400°F. Line a sheet pan with parchment paper and set aside.
Peel and cut yams into 1-inch cubes. Place yams in a deep skillet and just cover with water. Boil for 8-10 minutes, until yams are partially cooked (a fork should be able to poke into them, but they
should not be so soft that the fork easily breaks them apart when pierced). Drain the yams,
reserving 1⁄2 cup of the water for the sauce.
Meanwhile, chop bacon into pieces and cook over medium heat in a separate skillet until crispy and
browned.
Remove cooked bacon from the skillet and place on the prepared sheet pan along with the drained
yams.
In the skillet with the bacon grease, add reserved yam water, butter, brown sugar, maple syrup, chili
powder, salt, pepper, 2-3 sprigs of thyme, and vanilla. Bring mixture to a simmer, stirring well, until the sugar has fully dissolved into the sauce. Simmer 2-3 minutes longer to reduce sauce by about half.
Pour sauce over the yams and bacon on the sheet pan and stir to combine. Spread ingredients into a single layer.
Bake for 20-30 minutes, stirring halfway through, until all of the liquid has evaporated and the sauce begins to caramelize over the yams and bacon.
Serve immediately, garnished with a bit more fresh thyme, if desired.