Preheat your oven to 400°F and line a rimmed baking sheet with parchment paper.
Clean the portobello caps with a damp paper towel, remove the stems, and gently scrape out the dark gills using a spoon.
Brush the outside of the mushroom caps with 1 tsp of olive oil and place them gill-side up on the baking sheet; roast for 10 minutes.
While mushrooms roast, heat the remaining 1 tsp of olive oil in a skillet over medium heat and sauté the minced garlic for 1 minute until fragrant.
Add the ground turkey to the skillet, seasoning with sea salt, black pepper, fresh thyme, and rosemary; cook until the turkey is fully browned.
Stir the fresh baby spinach into the turkey mixture until just wilted, then remove the skillet from the heat.
Remove the mushrooms from the oven and carefully drain any liquid that has pooled in the caps.
Divide the turkey and spinach mixture evenly between the two caps and top each with crumbled goat cheese.
Return the mushrooms to the oven and bake for an additional 8-10 minutes until the cheese is soft and the mushrooms are tender.
Drizzle each stuffed mushroom with balsamic glaze before serving.