Prepare the dough: In the bowl of a mixer, combine water, dry yeast, and 1.5 teaspoons sugar. Mix with a wire whisk until combined.
Add remaining dough ingredients: Add sunflower oil, coarse salt, vanilla bean, and all-purpose flour to the mixer bowl. Using the paddle attachment, beat on medium speed for 7-8 minutes until the dough is sticky and smooth.
Let the dough rise: Transfer the dough to a bowl, cover with cling film, and let it rise until it doubles in size. This will take about 45 minutes in summer or up to 1 hour in winter.
Prepare the caramel sauce: Warm the cream in the microwave for about 1 minute. In a frying pan over medium-high heat, gradually add sugar to caramelize it, stirring carefully without using a spatula to avoid crystallization. Once the sugar is fully caramelized and golden, remove from heat.
Combine cream and caramel: Slowly add the warm cream to the caramel while stirring. The mixture will foam and thicken. Return to low heat and stir continuously until the caramel sauce is smooth and fully melted. Add a pinch of salt and cook for 2-3 minutes more.
Shape and fry the donuts: Remove cling film from the risen dough. Using your hand and a spoon dipped in sunflower oil to prevent sticking, pinch off pieces of dough and drop them into hot sunflower oil heated to medium-high temperature. Fry the donuts for 2-3 minutes, turning constantly with a slotted spoon to ensure even cooking.
Drain and serve: Remove fried donuts and place on absorbent paper to drain excess oil. Serve warm, dipped in caramel sauce and sprinkled with chopped roasted salted peanuts.