Melt butter in olive oil in a medium saucepan.

Add scallions and cook until softened (2 minutes).

Add heavy cream, vegetable stock, and saffron to the saucepan.

Bring the mixture to a boil.

Reduce heat and simmer until the sauce is reduced to 1 3/4 cups (15 minutes), stirring occasionally.

Strain the sauce through a fine sieve into a small saucepan and season with salt and pepper.

Keep the saffron sauce warm over low heat, stirring occasionally.

In a large, deep saucepan, bring ale just to a simmer.

Add shrimp and poach until cooked through (3 minutes).

Transfer shrimp to a plate using a slotted spoon, pat dry, and season with salt and pepper.

Blanch asparagus in boiling salted water until crisp-tender (2 minutes).

Transfer asparagus to paper towels to drain.

Spoon saffron sauce into shallow bowls.

Top with blanched asparagus and poached shrimp.

Serve immediately.