Step 1

Heat the butter in a medium skillet on the stove over medium heat until melted. Add the onion and cook, stirring often, until onion softens and begins to brown, 4-5 minutes.

Step 2

Add the garlic to the pan and cook, stirring, for 30 seconds. Remove pan from the heat.

Step 3

Place the chopped potatoes in the slow cooker. Transfer the contents of the skillet to the slow cooker, including any extra melted butter.

Step 4

Add the thyme, salt, pepper and broth to the slow cooker. Stir.

Step 5

Cover and cook on high for 3-4 hours or on low for 6-7 hours, until potatoes are soft.

Step 6

If using fresh thyme sprigs, remove and discard the thyme stems (most of the leaves will have fallen off into the soup).

Step 7

Blend soup to your desired consistency using an immersion blender or by transferring the soup in batches to a counter top blender. You can leave some chunks of potato or blend until smooth.

Step 8

Stir in the shredded cheddar cheese. Stir in the plain Greek yogurt or sour cream, if using. Serve with toppings as desired.