Here's the simple recipe from Epicurious: Twice-Baked Almond Croissants. Start with day old croissants. At United, four smallish-sized croissants cost $4.99. At that price, I might have to start making my own, no matter how laborious the process. The recipe gives instructions for an orange-vanilla syrup and an almond filling, made of butter, sugar, almonds, almond paste, and egg.
Four steps to assembling the croissants for baking:
1. Slice croissants in half lengthwise.
2. Brush vanilla-orange syrup on both halves of croissants.
3. Spread almond filling on one half of each croissant, mounding filling high in the middle.
4. Spread filling on top of croissant, and press toasted almonds into filling.
I might have eaten one for dinner alongside strawberries and salted caramel hot chocolate. That soft almond filling oozes out on the first bite. Yum!