Beets with Dill and Walnuts

Beets are ready when they can be pierced with a fork without much resistance. If it's not tender enough, press it again for a minute or two. While the beets are cooking, prepare the dressing.
Leave a 1-inch-thick root and stem on the beetroot; brush. Put in a 6-liter pressure cooker; add 2 1/2 cups of water. Close the lid tightly; bring to a boil over high heat. Reduce the heat to medium or as low as necessary to maintain high pressure; cook for 10 minutes. Remove from heat; let stand for 6 minutes. Release the pressure through the steam vent or place the stove under cold running water to relieve the pressure. Remove the cover. Drain and rinse the beets with cold water. Drain; allow to cool. Cut off the roots of beets, peel them. Cut the beets vertically in half; cut each half into 4 slices. Transfer to a medium bowl.Combine the vinegar and the following 5 ingredients (with the addition of pepper) in a small bowl; whisk to combine. Slowly drizzle with oil, stirring constantly with a whisk, until smooth. Combine the butter mixture with the beetroot; let stand for 15 minutes, stirring gently occasionally. Add the dill. Sprinkle with walnuts before serving.