If you're using frozen riced cauliflower, let it defrost while you work on the potatoes. Wash, peel, and cut the Yukon gold potatoes into uniform, small pieces to ensure even cooking. Then, add the chopped potatoes to a large pot or Dutch oven and cover them with cold water, adding 2 tablespoons of salt. Make sure the water covers the potatoes by about 1-2 inches. After that, bring the pot to a boil over high heat.

Once the water reaches a rolling boil, cook the potatoes for an additional 15-20 minutes, until the potatoes are fork-tender. When the potatoes are nearly done (around the 15-minute mark), add the riced cauliflower to the pot and boil for an additional 5-6 minutes until both the potatoes and cauliflower are fully tender.

Drain the potatoes and cauliflower using a strainer. Meanwhile, melt the light butter in the pot. Then, add the crushed garlic to the pot and sauté it over low heat for about 1 minute, just until fragrant, be careful not to burn it.

In a small bowl, mix the Greek yogurt and ranch seasoning. Add the drained potatoes and cauliflower to the pot with the butter and garlic, and mash using a potato masher. While mashing, incorporate the Greek yogurt and ranch mixture. Mash just enough to combine everything, avoid over-mashing. Then, serve these mashed potatoes and enjoy!