Melt the 3 tbsp unsalted butter in a large Pot over medium-high heat. Add the 2 medium shallots finely diced and cook, stirring occasionally, for 3–4 minutes until softened and translucent. Add the 3 cloves garlic minced and 1 tsp fresh thyme leaves or ½ tsp dried thyme and cook for 1 minute more until fragrant.

Wipe mushrooms clean with a damp paper towel — do not rinse, excess moisture prevents browning. Trim tough stems and slice to a consistent size so they cook evenly. Cut larger varieties like portobello into roughly 1-inch pieces. If using canned mushrooms, drain and pat completely dry; plan for just 2–3 minutes cook time since they're already cooked. Pre-measure butter or oil, garlic, and seasonings before heating the pan — sautéing moves fast.

Heat a large Skillet over medium-high heat. Add butter or oil and let it heat until shimmering. Add mushrooms in a single layer — don't crowd the pan or they'll steam instead of brown. Cook in batches if needed. Add a pinch of salt. Uncovered method: sauté over medium to medium-high heat, stirring occasionally, for 5–14 minutes. Thin mushrooms like oysters are done around 8 minutes; denser cuts or larger batches take 10–14 minutes. Portobello slices with onions over lower heat: 8–12 minutes. Covered method: cover and cook over medium-high heat until liquid releases, about 8–10 minutes. Uncover and continue cooking until liquid evaporates and browning develops. Add garlic early enough to soften but watch it — it burns fast. Add any finishing acid (cider vinegar, wine) in the last 1–2 minutes and let it cook off before removing from heat.

Pour in the 4 cups vegetable or chicken broth low-sodium preferred and add the 1 tsp Worcestershire sauce, 3 tbsp unsalted butter, and ¼ tsp black pepper freshly ground. Stir to combine and bring to a gentle boil, then reduce heat to medium-low and simmer for 10 minutes, stirring occasionally, until slightly thickened.

Use an Immersion Blender (or carefully transfer half the soup to a Blender) and blend about half the soup until smooth, leaving the rest chunky for texture. Return everything to the pot.

Stir in the 1 cup heavy cream and warm over medium-low heat for 3–5 minutes — do not boil. Taste and adjust 3 tbsp unsalted butter and ¼ tsp black pepper freshly ground as needed. Ladle into bowls and garnish with 2 tbsp fresh parsley chopped and an extra crack of ¼ tsp black pepper freshly ground. Serve with crusty bread.