Cook the blueberries with a little butter for a few minutes, until they have become soft. Blend them and set aside the puree.
Heat a little olive oil in a saucepan and sauté the finely chopped onion until softened. Add the speck cut into strips and let it brown, stirring occasionally.
Add the rice and toast it for a few minutes. Deglaze with red wine and let it evaporate, then add two ladles of broth. Season with salt and continue cooking over low heat, occasionally adding hot broth and stirring frequently. About halfway through cooking, add the blueberry purée and continue to moisten with hot broth until the rice is fully cooked.
Remove the pot from the heat, season with chopped rosemary, and stir in butter and cheese to taste.
Garnish to taste with a few whole blueberries and serve.
