Melt Butter. Start by melting butter in a skillet over medium heat.
Cook Peas. Add frozen peas (no need to thaw!). Cook 6-8 minutes, stirring regularly, until the peas are a vibrant green color, plump, and tender. If you taste one, there shouldn't be any crunchy bite (a sign they're underdone), and they shouldn't be mushy (overdone).
Taste & Season. Add garlic, salt, and pepper, then stir 30-60 seconds. Taste and add additional seasoning if desired--a pinch of sugar, more salt & pepper, or other fresh seasonings.
Serve & Store. Enjoy seasoned peas right away, or store leftovers in an airtight container. (The butter or olive oil will solidify and harden in the fridge--this is normal! It will easily melt again when you reheat leftovers.)
Since the stove you use and the pan you use can have an impact on cooking time, it's best to look for visual & sensory clues to know when the peas are done. They should be vibrant in color, plump, and when you bite into one, they should be tender but not mushy.