Place raw red potato cubes in a large steamer basket over a large pot of boiling water. Cover and steam until very tender, 25 to 30 minutes.
When potatoes are nearly tender, melt butter in a small saucepan. Add garlic; cook and stir until fragrant, about 1 minute. Add salt and olive oil; stir until just heated through. Remove from heat.
Transfer tender potatoes to a large bowl. Pour olive oil mixture over and mash with a potato masher to desired consistency. Garnish with chives if desired and serve.
Video
Notes
If you don't have a steamer, feel free to boil potatoes instead. To a large pot, add cubed potatoes and enough cold water to cover by 1-inch. Bring to boil over high heat. Reduce heat and let summer until potatoes are tender. Drain and proceed with recipe.
If you're not a fan of olive oil in these mashed red potatoes, no problem! Just increase the butter to 10 tablespoons and skip the olive oil. Likewise, if you want to use just olive oil for a vegan / dairy-free version, use 10 tablespoons of olive oil (1/2 cup + 2 tablespoons) and skip the butter.
To make Garlic Mashed Red Potatoes, mash in the roasted garlic cloves from one or two heads of roasted garlic along with the olive oil mixture before serving. To roast heads of garlic: remove the outer papery skin and cut off the top 1/2 inch of the head to expose garlic cloves. Drizzle with olive and wrap in aluminum foil. Transfer to a baking dish or baking sheet to catch any drips and roast at 400˚F for 35-40 minutes until tender and lightly brown. Let cool slightly before squeezing cloves out with your fingers or lifting out with a cocktail fork.