Sauté the sliced mushrooms. First, to a skillet over medium-high heat, add a tablespoon of the olive oil. When the oil is hot, add the sliced mushrooms and a pinch of salt and black pepper. The salt helps the mushrooms release water. Sauté for about 3 minutes until the mushrooms get a bit of color on them. Then, add the unsalted butter, minced garlic, thyme, lemon zest, and lemon juice. Sauté for about 3-4 minutes until the mushrooms are tender.
Grill/toast the bread. First, brush the thick bread slices with olive oil on both sides. Then, grill the bread slices in a skillet, grill pan, or cast iron pan for a couple of minutes on each side over medium-high heat until lightly browned and toasted.
Get the assembly board together: the grilled/toasted bread, the sautéed mushrooms, the soft goat cheese, and the avocados.
Assemble the avocado toast by adding mashed avocado first, then the sautéed mushrooms, and chunks of goat cheese. Optionally, garnish with some fresh thyme.
