• Whisk first 5 ingredients in medium bowl
• Place milk and butter in small saucepan; stir over low heat until butter melts and thermometer registers 110°F (if mixture gets too warm, cool until temperature returns to 110°F)
• Pour warm milk mixture into flour mixture and whisk until smooth. Cover with plastic wrap and let stand in warm draft-free area until doubled in volume, 1 to 1 1/2 hours
• Whisk buckwheat batter to deflate; then whisk in eggs
• Do ahead Can be prepared 1 day ahead: Transfer to large bowl, cover and chill (may increase in volume; rewhisk before using)
• Preheat oven to 200°F
• Heat griddle or large skillet over medium heat; brush lightly with melted butter
• Working in batches, pour 2 tablespoons batter for each blini onto griddle, spacing apart
• Cook until bubbles form on top and begin to pop, about 1 1/2 minutes
• Turn blinis; cook until golden brown on bottom, about 1 1/2 minutes
• Transfer to baking sheet; tent with foil and place in oven to keep warm while cooking remaining blinis
• Do ahead Blinis can be made 1 day ahead. Cool, cover, and chill; brush blinis lightly with melted butter and rewarm on baking sheet in 350°F oven 5 minutes
• Arrange warm blinis on platter; garnish as desired

Instructions for Thermomix:

• Scale milk and butter into the TM bowl; stir for 2 minutes at 37°C at speed 1-2 until butter melts
• Scale first 5 ingredients into the TM bowl with warm milk and butter mixture; whisk for 15 seconds at speed 2-3 until smooth
• Cover with plastic wrap and let stand in warm draft-free area until doubled in volume: 1 to 1 1/2 hours
• Whisk buckwheat batter for 5 seconds at speed 1 to deflate
• Set time to 1 minute and speed at 3; whisk in eggs one at a time, through the hole in the lid
• Cover and chill overnight to intensify flavour; the next day, rewhisk before continuing

Next Day:

• Preheat oven to 200°F
• Heat griddle or large skillet over medium heat; brush lightly with melted butter
• Working in batches, pour 1 to 2 tablespoons batter for each blini onto griddle, spacing apart
• Cook until bubbles form on top and begin to pop, about 1 1/2 minutes; turn blinis; cook until golden brown on bottom, about 1 1/2 minutes
• Transfer to baking sheet; tent with foil and place in oven to keep warm while cooking remaining blinis
• Arrange warm blinis on platter; garnish as desired