First, grease a 9x5-inch loaf pan that fits in your pressure cooker. No sticking allowed here.
Mix the oil and sugar in a large bowl. Whisk ’em good until they’re blended smooth and kinda glossy.
Zest the lemons right into the oil-sugar mix so you don’t waste any zing. Then juice the lemons and add that to your bowl.
Crack in the eggs one by one, stirring well after each. Then fold in the yogurt and vanilla if you’re using it.
In another bowl, sift together the flour, baking powder, and salt. This keeps your cake light, not dense.
Pour the dry ingredients gradually into the wet, mixing gently just until you don’t see flour no more. Avoid overmixing or cake feels tough.
Fold in the blueberries real careful so they don’t burst all over your batter. You want pretty pockets of blueberry, not purple mush.
Put the batter in your loaf pan, smooth the top, and carefully place it in the cooker pot. Seal the lid and cook on high pressure for about 35 minutes, then hit quick release to unlock your treat.
Notes
Don’t forget powdered sugar for dusting after the bake, if you're feelin’ fancy.