Sitruuna-vadelmamuffinit

Yes, but fold them in straight from the freezer without thawing, otherwise they release juice and tint the whole batter pink. Toss them in a little of the measured flour first so they stay suspended instead of sinking. Frozen berries also chill the batter, so check for doneness at the upper end of the 25-30 minute range.

Sour cream or crème fraîche work almost identically since the recipe only uses 80 g and relies on the yogurt for moisture and tang. A thick plant-based yogurt is fine too, just make sure it is unsweetened so the 80 g of sugar stays in balance. Avoid thin drinking yogurt - it makes the batter too loose to hold the raspberries and the streusel on top.

That almost always comes from overmixing after the flour goes in. The recipe deliberately says to stir just until no dry flour remains - a few lumps are exactly right. The airiness should come from the eggs and sugar beaten for at least 2 minutes, not from working the batter once the flour is added.

The streusel is the ideal make-ahead component: rub the 30 g flour, 20 g sugar and 20 g butter together and keep the crumbs in the fridge or freezer until you need them - cold butter only improves the texture. The batter itself should not sit around, because the baking powder starts working as soon as it meets the wet ingredients and the lemon juice. Do measure and mix your dry ingredients ahead, though, so baking day is just a matter of combining.

Cool them completely on the wire rack first, then keep them in a loosely closed container at room temperature - an airtight box softens the streusel. Thanks to the yogurt and oil they stay moist for a couple of days, and the lemon flavour actually settles in nicely. For longer storage freeze them individually and reheat briefly at 180°C to crisp the topping back up.