In a stock pot add butter and oil over medium heat. When butter melts add onion, shallots, and leeks. Cook stirring until translucent @ 10 minutes.
Add chicken stock, white wine, and potato to the onions. Bring to a simmer. Add herbs. Cook for 30 minutes, and discard the herbs. Puree with an immersion blender.
Add kale, heavy cream, lemon juice and salt and pepper to taste. Cook until kale wilts and serve warm with cheese thins. If too thick add more stock.
Asiago Cheese Thins
In a small saute pan, toast sesame seeds until golden brown over low heat, stirring constantly. Remove from heat and cool.
In a food processor, combine flour, baking powder, and salt. Pulse to combine and add butter and cheese. Pulse again until it looks like pebbles. Add ice water slowly until dough forms a ball. Remove dough from processor.
Form a log with the dough and roll in sesame seeds (optional). Wrap dough in wax paper and store in the refrigerator overnight.
Preheat oven to 400 degrees. Slice dough thinly (less than 1/4") and place on a baking sheet. Bake for 8-10 minutes until golden and cool on a rack.