Cook zucchini. Heat olive oil in a large skillet over medium-high heat, until shimmering. Add zucchini slices in a single layer (some overlapping is fine, but not multiple layers). Cook for about 5 minutes, until zucchini is starting to brown.
Cook butter and garlic. Push the zucchini slices to the sides of the pan, making an open space in the center. Add the butter and wait for it to melt. Add minced garlic to butter and saute briefly, until fragrant.
Mix zucchini with garlic butter. Stir everything together and season with salt and pepper. Mix gently until butter is absorbed into the zucchini.