Heat 1 tbsp of olive oil and 1 tbsp of butter in a large pot over medium heat.

Add the chopped onion and a pinch of salt. Cook until translucent, about 4 to 5 minutes.

Add the garlic and cook for 30 seconds until fragrant.

Increase heat to medium-high. Add sliced mushrooms and a pinch of salt. Cook without crowding, allowing them to brown and release liquid for about 6 to 8 minutes, stirring occasionally.

Push mushrooms to the side, add remaining 1 tbsp of butter, and sprinkle flour over the mixture. Stir to coat and cook for 1 minute to remove raw flour taste. If using no flour, skip this step.

Remove the pot from the heat briefly and stir in paprika, then return to heat.

Pour in the stock, add bay leaf, and bring to a gentle simmer for 8 to 10 minutes.

Temper the sour cream by scooping a few ladlefuls of hot broth into it, stirring, then whisking back into the pot. Add cream if using, and heat through gently without boiling.

Taste and adjust salt and pepper. Remove bay leaf. Finish with a squeeze of lemon if desired and garnish with chopped dill or parsley. Serve hot.